ThisWhen I pull up, I say "how many will be riding?". If they say 5 or more. I offer options of canceling for an XL or getting another uber in addition to mine. The whole "we aren't going far" thing is followed up by "then you won't mind spending an extra $5 so that so I can legally take you. After all, $10 divided by 5 people is only $2 each."
If your polite they usually are cool.