Always good to look out for one's self.

Any TA, contract or not, is unable to do the job without one's credit card info. Yes, fraud can happen as is the possibility anytime the card is used anywhere.

I appreciate the notions of setting up response expectations and emergency contact info.

I would add that I now am leary of private email solicitations here at FT. Even as I acknowledge the bad apple is uncommon and many such offers are genuine in wanting to help.