Simple question but I've spent some time searching and can't find an answer. Do non-battle schticks stack or do you only get the boost effect from having multiple copies in play?

A specific example is Haley's Sneak Attack. If she has all three copies in play *and* both her longbows is her defense +7 and her attack +7 at range 0? Or does it only become d+5/a+5?

To put it another way does she get the +1/+1 from the second and third Sneak Attacks in addition to the boost effect? Or does she only get +1/+1 from the first Sneak Attack and then only the boost effect from the 2nd and 3rd ones.