You'd be wasting time tagging or flagging such throwaway accounts. They will simply create a new one and keep doing what they do. I suppose reporting such posts and getting the user banned is more efficient.
Like they always say that "merit abuse is not morderated' or something in those lines, so, I doubt if they would ban the user if reported.
Personally, i think what OP is doing is commendable. Even though they are throw away accounts, he makes them sweat trying to create a new untagged account every time they want to advertise