I went on LiveNation, and this is what I can gather:
For JB, it has a few dates titled "The Burning Up Tour." Then, the title goes away and is simply "Avril Lavigne and the Jonas Brothers." Once those dates are done, it goes back to saying The Burning Up Tour.
If you look at Avril's, she has a bunch of dates that say "Avril Lvigne with Boys Like Girls." After that, it goes to "Avril and the JB." Now, I know BLG are opening for Avril, and theirs says WITH. JB says AND. And on JB's myspace, they pretty much claim that date as theirs.
So, I'm thinking that Avril and JB are sharing the set, not having one open for the other one.
But I wish Avril was only opening... I agree with everyone else... I did NOT pay $100 to see JB for 3 songs and have the concert dominated by Avril.
Also... my mom told me that the lesser acts are mentioned last. On Livenation, JB is mentioned last... but on Ticketmaster, Avril is mentioned last. So that confuses me more than anything. Who is going to be the lesser act for the show (if there is one)?
Wow, that was long. Sorry!