Authorized Resellers regional options

Hi,

As you may know you can check if a key is regional via SteamLocks, the successor or domain change of http://www.steamlocks.tk/. In their second page where you choose among stores, there are many options to regional shops of these authorized resellers.

My questions are:

• Are these regional shops necessarily sell regional keys unless otherwise stated?
• Are there other sites or domains to regional shops, or is it purely visitor IP based?

As far as I know Amazon is .com and .co.uk. Same goes for GamersGate except I don't know the EU version. I thought both Humble and Nuuvem were single shops. As for GetGames I thought it was single shop too, until I found GetGamesME which is not in the list. Shops lack GreenManGaming but I know that GMG and GG are using IP based choices since they sometimes show unavailability for US exclusive titles.

I'd like to hear your experiences, thoughts about these...

L3GA

Thx