Traditionally the other party had some ads but generally laid low during the opposite party's convention. It was a courtesy tit-for-tat. Apparently, whether Biden is doing a speech and/or fundraiser, it is yet another precedent that opens them up to Newtonian reaction. In 2008 O and Co. destroyed the former precedent of federal matching funds - fine.
If Biden is clearly trying to steal some thunder - Lord make him say something stupid again - then Ryan should make his presence known during the D show in Charlotte.
Given the area, I think that Ryan could outdraw the president. Wouldn't that be a kick in the pants!