Looks like you could use some help

(Talking to David)

A middle-aged man dressed in average clothes walked confidently up to the man who'd just come out of the bathroom. "Pardon me, but may I suggest you go back to the bathroom and tidy yourself up a bit more? Those men in the suits over there, seated right next to where I saw you earlier, are law enforcement of the federal type and likely to be suspect of dilation of your pupils and the white powder residue to have on your coat... just one friend to another..."

The man smiled without waiting for a response and turned back to the bar. "Bartender, I can see these men here are on the job and I'm very glad to see not drinking while on it, but who could resist these burgers, eh? As the son of a former lawman I'd like to buy their lunch."

The men smiled and were surprised the stranger had figured them out but he explained he was familiar with the style of their clothes - comfortable yet professional - and while Texas was an open carry State, he could tell these men toted government issued firearms.

Seeing them off a few minutes later, the stranger waited at the bar in what had been David's seat for him to return.