Most of these responses seem to be helpful hints about how to physically remove the sticker, however I haven't found these practical answers:
1. Does the sticker peel off easily provided you remove it right away?
2. If so, is there any reason I should not peel it off my passport (immediately) and affix it to my boarding pass instead?
As far as I can tell, the ICTS stickers (or whoever does the security questioning) have nothing to do with my passport; security or gate people just need to see that I got the sticker. So, does it matter if it's on the boarding pass instead of the passport? And, is there any issue with my doing this myself, or must I ask the sticker person to do it?