I think that for free trials, you shoud be able to do withOUT credit card's. Like, you started out as a really good company, but now, you need credit card's for free trial's.
And if you forget to cancel, then you need to pay. Sure, some services do remind you in advance to cancel, but I'm not alway's online. I can sometimes not be on my phone for a week! And that's my 1st reason, but still 1 more...
...And my 2nd reason is because I do not even HAVE a credit card, and I want to know if I like ot so I do not put ALL that work into making one until I know that I really like it!
So that's why I do not think that we should need a credit card for free trial's!