*We could play strip poker...*  "Oh, well, we'll think of
something."

I'd say that it's perfectly IC!

   But still, there's a bit of a difference. That time by your own 
admission Akane is present (so there is her implicit permission-- 

Konatsu is present for this one.  They played Hearts, remember?  (Hearts
needs at least three players for you novice card players.)  So fitting for
Ranma.  Love triangles everywhere.

King). Ukyo and Ranma playing strip poker alone, purely for fun (for UKyo 

She thought that.  She didn't say it.