Looking at the F18 (and the others presumably follow a similar pattern) at higher alpha, the LEX (leading edge extension) generates a very intense shed vortex which is aligned with the fin. Plenty of photographs about which show the shed vortex.
Yup. So much so that they had a big problem with veritcals cracking well before their expected service life was up. The fix is that strake on the LEX that looks bolted on as an afterthought, since it pretty much was.
As for airfoil's comments, I'd be interesting to read more about it. I always thought the strake/chine/LEX was just a massive VG to help keep the airflow "stuck" to the top of the fuselage and hence over the rudder(s). I don't claim to be an expert in high-alpha aero, so I could be wrong.