I am thinking of using Amazon s3 or even google drive for my website that has a few downloadable files. Problem is I don't really see how to stop spam in this case. Amazon s3 looks like a great way for spammers to give you a $100,000 bill. There is no captcha option and most have to be off site. Are there any hosts that can stop this (have captcha) or is this just a case of wait for a person to spam download and you are helpless to stop.
I can not find a lot on this issue to my surprise.