Confinement reads:
Action: Choose a character with STR 4 or lower. Until the end of the phase, that character loses a {MIL}, an {INT}, and a {POW} icon.
Say I declare a challenge and kneel my attackers. My opponent then plays Confinement, removing the icons on one of my attackers. I believe the targeted character would remain in the challenge. I can't remember where I read about this or a similar situation but the reasoning was that you only check to see if they have the relevant icon when you declare them as an attacker or defender and that removing the icon after the fact does not remove them from the challenge.
Am I correct and can anyone point me to a relevant rule that would explain it? Thanks.