Almost never through Rennt. It is arithmetic, not a promise.

When you Confirm a booking, those units are held for those dates and your storefront stops offering them. Own 3 bounce houses, all 3 out Saturday? Saturday shows unavailable for that item, automatically, with no action from you.

The one real hole: phone orders#

Rennt can only protect stock it knows about.

If someone calls and books your last tent and you do not enter it, the storefront will happily rent that tent to someone else. That is not a bug — the system genuinely does not know.

The fix takes 30 seconds: when you take a phone order, go to Bookings → + New booking and enter it right then. Not later. Later is when it gets forgotten.

Tap to enlarge

The second hole: a Request is not a hold#

A booking sitting as a Request does not reserve anything. Two people can request the same item for the same day. Whoever you Confirm first gets it.

This is why clearing your Requested list matters.

The third: your Qty is wrong#

Set Qty to what you can actually rent out at once, not what you own. Three tents, one torn = set 2. Rennt cannot see the torn one.