What happens in Vegas stays in Vegas.
of course, we were in Reno, so I did some research.
What happens in Reno, stays in reno for a while, and then goes to vegas for two weeks, and ends up in Cancun.
What happens in Tahoe seems to float over an air force base for a while before dissipating into thin air.
Apparently, what happens in Detroit is just covered with concrete and paved into the road.
I’m not too sure yet about Chicago. Leave your examples in the comments.

What happens in Chicago is either declared illegal by Hizzoner Daley and/or taxed into oblivion…
Whatever happens in Vegas gets broadcasted all over NWI anyway.
What happens in Seattle runs into Puget Sound the next time it rains. Nobody cares anyway.
What happens in Chicago just gets stuck in construction traffic.
What happens in Indianapolis just…well, nothing much happens in Indianapolis.
Close, hooierboy. What happens in Chicago falls onto the stripped concrete on the Eisenhower Expressway and gets paved over.
Jimmy Hoffa, call your office!
M
What happens in Portland washes into the storm drains, flows into the Willamette River (the largest north-flowing river in the US), then make a LEFT turn into the Columbia River (or the Multnomah Channel where it helps float my yacht), and out to sea.
[…] Of the ladies, I have to say this: thanks for your patience in putting up with us. Specificlly, to Keewee, the accent is one that usually just makes me take out my wallet. Good thing for me everyone was well-armed- otherwise, well, what happens in Reno… As for Mrs Riverdog, having spent your life putting up with HIM is bad enough, but the BS you’ve been through, and the strength you show in how you live your life? A finer, tougher broad I think I never met. Remind me never to piss you off. […]
What happens in New Orleans is evacuated and lives in Houston until the FEMA money runs out…
MC
What happens in Los Angeles gets shot up in a drive-by, then is broadcast on TV via helicopter in the ensuing slow-speed pursuit.