Except Thrash doesn't target, so not RAW IMO.If you know you're holding something, you can Thrash it around. One might say that implies targeting, but that's RAI (the implied version of RAI, not necessarily the intended version).
Sadly, whether one knows they're holding something circles back to Foil Senses re: touch...
This is adjudication territory IMO, and were rigorous rules laid out, they'd likely become too exploitable and/or fall apart given all the size, limbs, and other physiological/magical variance.
Thrash does have a target: your grabbed foe.
A lot of good points
I actually agree with you on all of this and think Concealed should be ignored in these cases, at least until it's reworked. But to answer your question on how I'd rule if I said it applied:
1) You do the Whirling Throw flat check before rolling Athletics. If you don't pass, you don't roll Athletics and just waste the action.
2) Yes, a failed flat check is a miss for the purpose of those feats.
TheFinish wrote:That being said, it'd be nice to have a sidebar that said something like "Unless noted on a creature's statblock, X is a Precise Sense, Y is Imprecise, Z is vague." for Sight/Sound/Smell/Taste/TouchYou might want to check the post and link I quoted 5 posts above yours.
I've read that section, I find it unsuitable mainly for two reasons:
1) As I said, I think Touch is Imprecise, not Vague, especially going by the descriptions the book itself provides. Touch has less range than smell (at least, for those of us who aren't Mr. Fantastic) but it provides a ton more detail than smell or even hearing in most situations.
2) It doesn't provide ranges, which isn't super necessary but it leads to things like a character being able to use Touch to Seek any 30 foot burst within LoS with one action. Of course, since Touch, being Vague (allegedly) can only go Unnoticed->Undetected, it wouldn't do anything according to seek.
Compare to Mutants and Masterminds: http://i.imgur.com/Iw5LIli.jpg
I'm not saying PF2 needs that level of detail, the Perception/Concealment rules just need a bit of polish.