Well considering Beatty is a public park the trails never officially closes or opens due to weather. Obviously as bikers we unofficially denounce using rails while muddy.

That being said I think the amount of dryness needed to run on a trail is lower than that of biking. Foot traffic isn't quite as rough on damp trails as bike tires are. Sure some people would disagree with me but that's my opinion. 

I wouldn't bother your buddy about it.

relax...