I wonder what will happen if someone checks a bag on the first ticket, but the bag is delayed. I assume that the first airline won't want to deliver it to a hotel at the second destination. It could sit at the intermediate airport, but the passenger might well be using a different connection point on the return tickets.

Someone could also get in trouble if they are forced to gate check a bag using a system that delivers these bags to baggage claim rather than planeside. This is a contingency for which consumes cannot be expected to plan either additional time or travel documents such as visas. I can imagine fights over the request to check a bag when the bins are full.