You are right about preorder risk but since the top of the web site says "Especially catering for customers based in Japan! Our company may be based in the UK, but our IMEI-based sim unlocks work no matter what country you are in." and if preorder then should not deduct money from people's credit card, this is totally Fraud !
That thing at the top of their page says whatever country you are in. Mine says "Especially catering for customers based in Bermuda". The site is not a fraud site. They are legit and can get unlocks done, but only for the carriers they have listed as available. Never order the preorder, it means they cant get it unlocked (yet). I dont think they should have that option there personally.