Ser Cedric Payne might come to the tourney, and might have Podrick amongst his staff. His Westerland origins would likely put him on priority Inquisition watch, but he's not actually a Lannister so he should be let in.
On the one hand, A) I suspect Tywin Whammied all of his chief bannermen and put pet mages on them to ensure the enchantments would stick. And B) I think most Westerlanders are terrified of him enough that they wouldn't come anywhere near us without being explicitly ordered to do so by Tywin himself, lest they be suspected of treason.
And technically with all the Knights, some likely from prominent noble families, taking part in this tourney, the Crown is amusingly enough basically forced to ignore the entire affair as if it never happened or risk sparking off a civil war they're not any more prepared to deal with than we are ourselves. It's the more amusing dichotomy of the state of affairs that grabs me than anything else, the Lannisters can't act too overtly, frankly Tywin only got away with probably brainwashing his bannermen due to it happening inside lands he's basically got meticulous control and authority over. Hoster bitchslapped his remarks about not keeping his bannermen in line with an errant slap, and this makes entirely too much sense seeing as how in terms of dynastic alliances and political positions, Hoster has the support of two other Lord Paramounts, whereas the Reach has been outside paths to power for nearly a decade, Stannis is now in control of the Stormlands, and the Crownlands are split between Targ loyalists and lackeys bickering with each other.
Meanwhile, Viserys has the (still nominal but better placed) support of the Iron Isles, a slowly growing faction of Vale lords (probably enough to take them out of any war against us), a few major Riverlands Houses (with the rest probably ambivalent towards Tywin and Robert), somewhat cool but positive relations with the North (and constantly thawing), a debt of honor if not support from the current Lord of the Stormlands, and a heavily divided Reach that neither side is currently poised to take heavy advantage of. And
the entirety of Dorne.
That just about makes things even, honestly. Even without significantly major support from more, we have our own military forces (enough to fight a war, though maybe not necessarily come out smelling like roses), and all it would take is a couple of
really bad reversals for Tywin to start losing any allies he does manage to gain, seeing as how he trades on fear and gold, and if your allies fear the other side more, and don't think they'll live to spend the gold, they'll ditch you quickly.