I always put a CC on file. Additionally, if I am planning to use gift cards I put them on my account when I am checking in. About 50% of the time I will get a cast member who will swear up and down that it can't be done, no how, no way. I just ask the CM to check with a supervisor and then the supervisor gives the necessary training on how it
can be done.
The reason I like to do it on check in is so I don't have to stand in line again at check out (or multiple times during the visit)--or even worse so I don't forget because I am focused on packing up and getting off to the airport.
The reason they don't like to take it on check in is they are worried that I won't spend all the GC money and then it has to get credited back to my CC on file. (Apparently Disney prefers the cash flow to go the other way

) The Disney Share holders can rest easy though, for my part I have never had a refund in all the times I have done this.