The whole question of a space being adjacent to itself (what would be required for a trap to trigger when stepping on it, as opposed to next to it), had prompted me to write to FFG a while ago. I received a response from Nathan Hajek at the time which stated the following:
There are a lot of rules that use the concept of adjacency. Some were written while accounting for that a space is not adjacent to itself, and some, unfortunately, were not. As such, the execution of the mechanics is not always thematically sound. I could call each of these out, creating exceptions in the cases where it doesn’t make sense, but then players would have to wonder each time adjacency is used, is this per the rules, or an exception? So, unfortunately, I believe it is best to apply the blanket rule found on page 10 of the rulebook, that a space is not adjacent to itself. If players would like to make their own exceptions in the name of theme, I think they should, but I find it best to stick to RAW as much as I can.
Creative Content Developer
Fantasy Flight Games
I understand his point, and it is one of the reasons why I don't like home rules ... I happen to be a fan of abiding by RAW. Having said that, I think it would be nice, if and only if it wouldn't break something else, if a FAQ ruling was made that any space is adjacent to itself.