You make a very good point and it is something that every collector should be wary of, I have a display room which is locked when I'm not in it and also has a burglar alarm sensor linked to the house system.
I have shown about five people in total, friends I really trust, a couple of them just wanted to see the room and didn't really have an indication of the total value, they just asked about one or two items, strangely enough, their attention was drawn to my Palitoy factory sealed falcon which they see as the iconic toy. Their comments on my Palitoy MOC's were almost dismissive, which made me laugh a bit, "I remember that one" and "oh, you have two han solo's", not noticing the different sized heads.
Its just about being very careful really, when I buy things they are always delivered to my Mum's house for security, it just has to be as you know the value of Palitoy Moc's nowadays. I took the majority of my collection photos with a digital camera, hence not showing the location, that may be an option for you.
Anyway, if you decide to, look forward to seeing some of your photo's, I may put a few up as I haven't showcased for a while!!