Quote Originally Posted by Calthropstu View Post
He had stopped asking at every door.
I don't want to belabor this here as it probably deserves its own thread, but this is more than a little unfair. The player may not have thought to ask, but his character would have noticed the change in spell school - especially since he was using Arcane Sight rather than Detect Magic, which means he would have noticed the errant abjuration aura instantly without even needing to concentrate. At a minimum you should have rolled Spellcraft on his behalf, and even had he failed, that would have told him there was an aura on the doorway that he didn't recognize - a stark contrast to the illusion auras he had already spotted that were slathered over everything.

A "gotcha" moment like this might be fun once, but were I a player at your table, I'd be sure to punish you by asking a hundred questions every time I stepped into a new square, since that is effectively what you'd be training me to do if I want my character to survive.