We have a hot list but not a cold list for when we look at a profile but find we don't want to check them out again. You can't always remember all the profiles you check out and unfair to block them as they might message later.
I used a hot list for guys I like, and I used notes for people who are not honest on this site, for personal reminders. So don't fall into their repetitive pic collecting and the time-wasting trap.