Loverboy is on tour this summer. I only know this because The Tubes are the opening act and I'm on The Tubes mailing list.
No desire to see Loverboy, but I may buy tickets (if the tour is a go for this summer) just to see The Tubes. I hate that they are the opener and likely won't be allotted enough time to do a full length set.
I probably would not leave before the headline act goes on stage. But if they were not good, I might leave early and beat the rush.....