> I'm in the process of figuring out the scope of this issue and how to fix/report it
Don't bother, the merchants and card issues are well-aware of this. You're supposed to reconcile your card statement with your expected transactions, and dispute irregularities. If you attempt to fraudulently claim that you didn't perform a transaction, the issuer goes to the merchant to get a copy of the signature & uses it as proof you authorized the transaction.
If a fraudster forged your signature, you simply assert that the signature is not yours. If you attempt fraud here (sign in an unrecognisable hand), the fraud investigations will try to put you at the scene with CC TV recordings/handwriting matching/etc. Hopefully you have not signed any affidavits that the signature is not yours, because then you'll be up for perjury as well as fraud.
Don't bother, the merchants and card issues are well-aware of this. You're supposed to reconcile your card statement with your expected transactions, and dispute irregularities. If you attempt to fraudulently claim that you didn't perform a transaction, the issuer goes to the merchant to get a copy of the signature & uses it as proof you authorized the transaction.
If a fraudster forged your signature, you simply assert that the signature is not yours. If you attempt fraud here (sign in an unrecognisable hand), the fraud investigations will try to put you at the scene with CC TV recordings/handwriting matching/etc. Hopefully you have not signed any affidavits that the signature is not yours, because then you'll be up for perjury as well as fraud.