So, this is highly dependent on the size of the Detail you're hiding the contact in, and if ever Cryptic decides to modify the Foundry (or their engine) to catch overlap violations, this won't work anymore?
Yes, there are certain limitations, the type of the map for one has an effect on the Y axis. So with a few props and the spider (the smallest contact in the UCG right now) this is perhaps the only way around the problem
Neat tutorial! I'm really happy to see other people making them. It's a useful trick, but it's too bad that we have to use npc costumes for the console instead of something more generic.
You can use a ship costume.
Also, I used this idea of "hiding" a contact inside a detail but for a different effect. Basically, I wanted to blow up a ship but have the player see it named as well as provide a plasma leak animation to the detail.
You can see both of these in my latest mission (in my sig below) on the first and second map.
Well, I take you still haven't took the time to run through that mission. No worry thou, the trick is out and the branching dialogs made that approach obsolete anyway. But back in january, it was kinda advanced.