I went out and enjoyed it, though I felt the same about the Hild Bede reps at Walkabout, and I don't think I'd have minded staying in either. The main impetus of the open day for me was seeing the English department and I absolutely loved it.
I just feel a bit tentative because although I really liked Trevs' ethos, and most of the reps were friendly and informative, some did, as you say, treat it as something for them. One of them was very bubbly and a bit OTT when giving a tour with one of their friends, and then ignored the open day people afterwards. (I do feel a bit awkward saying this as Dobbs was one of the Trevs reps, but you were very helpful Dobbs and I put you in the friendly and informative camp.)
I got on really well with some of the people I met which was nice, but at times it did feel a bit like school. I'm slightly worried that if I go I'll end up feeling like I live in my current Sixth Form common room, which I tend to avoid as some people seem to dominate it and I don't feel I can really switch off. But as I said before, I know an open day is an artificial situation and that college life is probably a lot more comfortable in reality. And I don't want to base my perception of an entire university on a couple of people on one night, as some things like someone going through my bag, finding my camera and looking through my photos while I was getting them drinks really shocked me but obviously has absolutely no relation to what my college experience will be like.
It may be that I've focused for so long on getting into Durham, and worried so much about meeting my offer, that the actual experience has left me confused. Maybe I'm just messing with myself, but I just can't make up my mind on how I feel about it. I remember telling everyone else how much I loved it (and myself), yet now I'm ambivalent. The food was really good yet I think I may prefer self-catering, my room mate was a lovely person I had a great chat with yet I think I might not want to share, and I danced in the bar and went out to the clubs yet I think the social side might not be me.
Bah. I think I'll give my brain a while to sort itself out. I really shouldn't let myself forget how much I love the course and Trevs as a whole. Hopefully I'll have balanced things out by the time I've got my last UCAS response in.