Is this a huge problem though? Here in NOLA we have an incredibly popular delivery place that's cash only and won't split orders. Lots of times on game nights or whatever we put in an order for 5 or 10 people. Most have cash on hand and we just throw in however much we owe, but invariably a couple of people (different ones different times) don't have cash. So somebody with spare cash covers them and they immediately Venmo/PayPal that person. Why wouldn't that work in these situations? Your friend pays, you send her the money electronically, everyone's square.