I've not read every post but having a pink ID (and a bank account linked to it), was a requirement of our local Social Security office in order to continue paying the monthly (432 Baht) fee to retain access to the Thai healthcare system after stopping work here. I also got a very nice refund of my SS payments coz I didn't take up the option of the (microscopic) Thai pension. It also works for sending items at the post office and via courier (Flash etc.). It's a valid 13 digit Thai ID number which (in theory) is your DL, TIN and Social Security number. Someone mentioned using it to get a Rabbit card, it's my understanding that it's NOT acceptable for that (or an MRT card) but I've not worked for BTS for 2 years now. As others have noted, if it's easy to get a yellow housebook then the pink ID is a simple add on, if a yellow book is a nightmare then ...
