So he has all this confidence, because he's lightly soaked in tequila and in a public place. Only Party Poison himself has the audacity to be a total prick in a public place! So he's definitely got the jump on this trickster jackass this time around. It's what gives him the confidence to saunter up next to Gabriel, stick a hand in the liar's back pocket, and make a nonchalant grab at that little umbrella.