I will be attending a conference outside Paris in September and there is a list of recommended hotels. I have chosen one of them based on price, rating on booking.com, and distance from conference. All is good but now I am being asked to send my credit card information to reserve the room. I asked if there was an alternative way to reserve but the request was just repeated.
I think the university has negotiated for special rates for the conference which is why we were told to contact the hotels directly (and the emails were provided). But still I am not so keen on providing credit card information in an email.
Is this a common practice? Should I be concerned?