So they take the guy who doesn't need a band (TI), use his band, and they don't use the only actual band out of those 3 artists. I'm not even a fan of Fall Out Boy and I find that annoying that they only used Patrick.
To be fair, T.I.'s live backing band is REALLY good from what I've been told. But yeah, if you're doing a mashup, why not use the recognizable band to actually play.