Charlotte has a multi-purpose downtown arena that hosts basketball and hockey. Raleigh has a multi-purpose arena that hosts basketball and hockey. Doesn't it seem obvious that the Charlotte Bobcats and Carolina Hurricanes should play a regular season game in the other's arena?
It makes all the sense in the world, and would serve a dual purpose: First, people in another part of the state would be encouraged to become fans from the opportunity to see the team in person. A tiny percentage of those people might then choose to make the trip additional times to see those teams in their regular home. Interest is interest, no matter where the fan lives, after all.
Second, any loss in revenue from dropping a game from season ticket plans would almost certainly be made up by drawing a full(er) house for a mid-week game against a crappy opponent. You think the Hurricanes are selling out a Tuesday night game against the Edmonton Oilers? Absolutely not. And we know the Bobcats won't sell out their Monday night game against the Memphis Grizzlies. But they have a shot at it if those are the games they play in the other city.
Advertise the 'Canes during Bobcats games, advertise the Bobcats during 'Canes games... it's a win-win.