Since there have been a lot of cheating cases recently, I think Mikey should consider disabling hacking during the contest. A lot of people already have reported here and here, there are also multiple blogs I read but I can't find them again.
A possible solution might be to
disable live hacking in rounds (but that would make CF boring as other CP websites)
closely investigating the accounts who lock the problems in their room (definitely the ones who try to view others' solutions)
a deep plagiarism check may be applied to only those solutions that were viewed during the contest, and repeated occurrences might raise suspicion on the person locking his/her solution.
Need some efficient solution MikeMirzayanov