I think you're all reading too much importance on what is or isn't written in the ToS. What any site can do (or can be forced to do) is defined by the laws they operate under completely regardless of what the ToS says. A site can't just write a line in their ToS that justifies them to "just lock an account or freeze funds on a whim" if that is effectively theft and illegal. It would be struck down as an unfair contract.
If you think anything about freebitco.in changed when we updated the ToS you are wrong.
Which world are you living in? So many sites(Including popular sites) are already using the TOS as their shield cleverly in order to justify themselves and avoid paying out customers even though it's unethical.
Only time will tell whether your site will follow in their footsteps or actually do whatever you boldly stated.