Durthag,
I've a favor and question to ask you;
Is it possible to detect magic using whatever sort of spell or scrying device?
If it is, would you be able to go into a non-protected Spellguard Building and cast varying spells of power, while having another trained in the arcane attempt to detect it's use?
Secondly, then go into a Protected Spellguard Building and cast varying spells of power, while having another trained in the Arcane attempt to detect it.
Should you still be able to detect in a "Protected" Spellguard Building (Those with the sigils) I would then ask you to travel a distance from Sanctuary, perhaps a mile or two and have a partner cast varying spells inside this structure after you arrive at your destination (have him wait a set amount of time). I would then wish you to attempt to detect this use.
The purpose of this experiment should be obvious; Do determine if these buildings are truly protected or not.
I hope this piques your interest.
Ivandur Reynolt