Some way, when a warning is issued you should get an email explaining the issue. You do not need to say from whom. Being subjected to a false allegation is not right either. You should not have to wait till the banned pops up because someone does not like your profile especially if it does not violate TOS, I realize moderators are there on a "complaint report", but that does not necessarily make the report Correct. A person should know the particular violation "if there is one.