Are we tipping Curbside Check-in?

I've been using curbside check-in for years but on a recent trip home from Newark the guy at curbside the whole time he was checking me in was talking about a cash tip. He didn't do anything exceptional - just the bare minimum of his job. But I didn't trust him to not bring my bag in if I didn't tip him cash.

Is he part of the Mafia or have I been a monster, using curbside and not tipping?