I know right? Still, I imagine her contract with Dan has a clause that states while she can decline from being an active participant in TF hijinks, Dan can still use her for non-canon and demonstration purposes.
That said I'm wondering where Dan's thought train went on the height issue. He said Susan in MV2-5 would end up being 6'3.53" tall and while that is taller than Justin, it's not entirely "OMG THATS TALL!" Then again I'm 6'4.5" so I may be biased a bit here. :)