You can't see the buyers id anymore for items they are bidding on or on sold items. So OP would be unable to do that, as they wouldn't be able to see buyers full ids.
Then there is transaction interference, which used to be a problem in the past, when buyers ids were visible.
Members are not allowed to interfere with another member's transaction.
Members are not permitted to email buyers in an open or completed transaction to warn them away from a seller or item.
I can't how the OP would have access to ids that have purchased items recently, unless they have transacted with them.
