Even if a moderator believes its revenge they shouldn't remove it if the user has a valid reason. If someone -reps a user then several hours later that person who got deducted rep decides to -rep them back but has a valid reason to do so i.e posting off topic then it should be left alone. For example, if you -rep me then I -rep you for posting off topic yet the rep I gave you gets removed it's basically saying 'You can't -rep this user even though you have a valid reason as they just -rep'd you so we believe it's revenge rep' it puts a cap on the rep you can give to that user and if people go around dishing out -reps they deserve what they give out, it'll show them they shouldn't be negative. I could never see moderators removing +reps, I +rep you then a few minutes later you +rep me, it's the same concept. To sum up my argument, there's no way to draw a line. The only changes I could see being beneficial but I wouldn't agree on nor others, would be to hide all negative rep usernames, vip or not.