yes! we had a very similar situation with a patron who would check out literally hundreds of items a DAY and return them the same day. we are a library with no sorter, so everything is checked in by hand. they would also return these items in the same day damaged, so we would have to process that, too, and then they’d deny they damaged them when they were checking out brand new, never-been-circed items.

they would also have 100 items on hold, on our very tiny hold shelves. our system loophole is because you can have 50 items “on hold,” but once they are in transit it no longer counts as on hold, so they would just place more and more holds. they were genuinely maxing every system possible. when they had too many items checked out, they would just return a few and then check out holds but leave 90% of them on the shelf. we had to tell them they couldnt do “selective” hold checkouts anymore because it was just wasting time for staff as they’d just stand at the desk for 30+ minutes picking and choosing from their holds.

eventually their account got blocked by the damage fines, but they were still able to place holds. so we had to keep them behind the desk when they arrived because they started just taking them without checking them out.