When I was at Uni in the 1980s noone took parents with them to open days or anything else.
Nowadays it is very common to see parents at open days an I would say that at Heriot-Watt as many as 50% of prospective students come with parents.
Google parachute parents and look at the articles on BBC news.
I am not going to express an opinion on whether this is a good trend or not, but you have to cut the apron strings sometime.... If your parents take you to the open days and go on the tours, fair enough. But FGS - don't take them into your interviews with you - it doesn't look good at all.