[US] Odd sidewalk interaction today – was it a scam?

Earlier this evening, my wife and I had taken our kids to the Cheesecake Factory. While we were waiting for valet to bring our car, two disheveled individuals, a man and a woman, approached us. They asked if they could use my wife’s phone because theirs was dead. Strange.

My wife, always cautious, hesitated and asked what exactly they wanted. The man explained that they were trying to buy a car and that their phones had died. And as some sort of proof, he revealed an envelope stuffed with a large amount of cash. This sent off both of our scam radars, and we said we had to leave.

Then they became increasingly insistent and started escalating the situation. Another red flag.

For better or worse, to keep things from escalating in front of the kids, my wife offered to send one text message on their behalf. They provided us with the number and asked us to write something to the effect of “the people buying the car from you are at such-and-such location and their phones are dead.” My wife added, “I’m a stranger texting on their behalf. I’m leaving now, please don’t respond to this number.”

We all got into the car and left. My wife immediately blocked the number, and at no point was her phone in their possession.

Was this some kind of hustle, or were these just some sketchy-looking people having a bad day?