Booking a name in helps if you are already with your missus.. Harder if your checking in alone and your partner is to 'join you later' though I have taken the p1ss in some hotels.. checked in as a double (when they had a joiner charge) and said my GF would join me later, when they ask for your GF's name just say 'lek' or 'poo' or any usual BS BG nickname.. They tend to hate it but if you just say you cant remember or pronounce her real thai name (act dumb farang) theres not much they can do..
Of course it fails on night 2 when lek is lek2 instead of lek1 but it gives you some wiggle room
I have no problem with taking ID names or even ID.. Thats a way to protect the guests from rip offs and a lot of good BKK hotels that are still GF do that, which doesnt bother me.. A small joiner fee is not the biggest of issues but I hate a place that gives them a hard time or cops an attitude to them..