The power block for a hat of disguise does not say when the Illusion ends. My players ended up coming to blows with someone from whom they were disguising themselves. Does the illusion end at the initiation of combat? When the players dismiss it?
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Just remember: You, too, were once a total "n00b." And yes, your questions were stupid at the time, too.
Powers normally last until the end of the encounter, or for five minutes, whichever is shorter. The hat is not an exception since it doesn't say that it is.
The rules don't actually specify when an encounter ends, so a DM who says that a combat is a new encounter is certainly acting within RAW. Some DMs do this to prevent players from entering combat with pre-existing buffs (because to do otherwise would be unbalanced); other DMs are fine with letting things persist (because to do otherwise would be silly).
This is actually a hot issue for certain powers. Players would love to start combat with e.g. Wrath Of The Gods up, without having the party to start in 'fireball formation' and to delay until the paladin's turn has gone. Likewise, the wizard power Minute Meteors is a good spell if the DM allows you to enter combat with it pre-cast, and a bad spell if the DM does not. YMMV.
Thanks KG. You're always a source of wisdom around here.
Follow-up: Would an obvious deformity, such as a peg-leg or a hook hand, be covered by the illusion?
I would say "yes", but noting that in certain circumstances, having an illusionary leg or hand could be troublesome; the person with a pegleg would need to bluff why they were "limping" (not to mention explaining their weird tracks they leave behind), while a person with only one functioning hand is going to have trouble using a knife and fork, reading a book, etc.).
Normally you would tend to just make one Insight check to discover the disguise, but I would allow a second (or third) in those circumstances.
I would say "yes", but noting that in certain circumstances, having an illusionary leg or hand could be troublesome; the person with a pegleg would need to bluff why they were "limping" (not to mention explaining their weird tracks they leave behind), while a person with only one functioning hand is going to have trouble using a knife and fork, reading a book, etc.).
Normally you would tend to just make one Insight check to discover the disguise, but I would allow a second (or third) in those circumstances.
M'kay. I see what you're saying. I just wasn't sure if there was a clause I was missing somewhere about limitations on either this illusion in particular or disguising illusions in general.
For the curious . . .
Spoiler
My players infiltrated an enemy fortress disguised as the enemy's elite guards. However, their ruse was blown instantly because the elite troops use special magic equipment that the players couldn't replicate, and they were recognized as phonies. This led to combat in which the players were victorious.
My questions in this case: Did the recognition that they were fakes cause someone to see through the illusion? Did the combat cause the illusion to vanish? One of the PCs has a glass eye, or in this case, he's a dwarf with a giant emerald eye. Was that visible through the illusion? The enemy is going to be using "Speak with Dead" on the killed troops, they'll want to know who was responsible.
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Just remember: You, too, were once a total "n00b." And yes, your questions were stupid at the time, too.
My players infiltrated an enemy fortress disguised as the enemy's elite guards. However, their ruse was blown instantly because the elite troops use special magic equipment that the players couldn't replicate, and they were recognized as phonies. This led to combat in which the players were victorious.
My questions in this case: Did the recognition that they were fakes cause someone to see through the illusion? Did the combat cause the illusion to vanish? One of the PCs has a glass eye, or in this case, he's a dwarf with a giant emerald eye. Was that visible through the illusion? The enemy is going to be using "Speak with Dead" on the killed troops, they'll want to know who was responsible.
No, a giant glass eye would not be instantly detectable through the illusion. As Kurald said, the illusion would "break" after about 5 minutes, although note that there is no daily limit on the number of times the Hat of Illusion can be used; you could just reactivate it. It wouldn't be inappropriate to rule that the disguise (unless broken magically) still continues until the players deactivate it).
Technically, all that's needed is an excuse to "break" the illusion. I'm going to assume you just ruled that their illusion was "broken" but didn't actually have an idea how? Here's a few suggestions to "cover" your butt (although in the future, I would reward their creativity):
A single enemy (perhaps a BBEG) with a high enough passive perception, who signaled the rest
Some secret call sign/action which the guards would know, but the PCs did not (allowing for active perception/insight checks).
Perhaps some magic ritual (make it obtainable from the PCs) grants people the ability to detect illusions. For example, the level 11 ritual "Banish Illusions" (Eberron Player's Guide)
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When does a Hat of Disguise turn off?
