We don't have a formal exception policy (for the sake of simplicity), but to be honest there's so many prompts (almost 190 on the gen list alone) that the chances of you getting a few in particular is fairly low. Also, you're not obligated to write ANYTHING that shows up on your card. Pretty much everyone's going to get something on their card that just doesn't work for them, for whatever reason. I've always found that that's one of the fun things about bingo challenges: finding the shapes/lines/bingos that I CAN do amongst all the things that I can't. ;P

We don't say no because we don't care, just because we've seen other challenges where they do allow exceptions, and it can get complicated when you have to vet cards for what folks wanted and didn't want, especially when the challenge gets big.