As well as the account activity and post count matching, there are far too many small signs that they could give attracting attention to themself thus getting their account tagged.
If you were excluding accounts from being selected for campaigns when you were extremely busy in your managing days, you probably did us all a favour otherwise the alt-accounts and account farmers would be feeling empowered as they would have been rewarded for their duplicitous conduct.
When activity and post count match it's almost a guarantee that it's an alt and part of a farm IMO. When I was managing most of the campaigns on the forum, I would not hire these accounts most times.