I voted no trial. I never did one as a buyer, and of course my last 2 were bought at the track, so I couldn't even get on them before buying them!
I would not be comfortable sending my horse on a trial. ANYTHING can happen, it's just too risky. I have no problem having the person come ride the horse on location. I would not want them to trailer my horse anywhere before buying her. Again - too risky. I might trailer Horse to a different location myself, for them to ride there, but I'd rather not do it.