Join Date: May 2000
Location: Houston, TX, USA
Programs: UA Platinum, AA Lifetime Platinum, DL Platinum, Honors Diamond, Bonvoy Ambassador, Hertz Platinum
Posts: 8,179
Upon entering, declare "1 day" as your intended length of stay and be prepared to show your onward ticket or boarding pass.
They never ask any questions upon leaving. They just check to make sure your passport is valid, that you haven't overstayed, and that you have no arrest warrants active.