You do not need to surrender your old passport in BKK while you are waiting for a new one. Also you do not apply for a new passport at the British embassy in Bangkok, you apply at UK Visa Application Centre
The Trendy Office Building, 28th Floor, Sukhumvit Soi 13, Bangkok.
I agree, just trying to show their perspective. I have also seen a couple of posts here where people have reported late ( as in after 90 days, but not after 97 days) and been fined.
There used to be something called national pride, Obviously it is something that you dont feel the need to project when overseas. After travelling, to and working in over 100 countries over the past 37 years, i can comfortably say that I am pleased that i left a good impression and was never looked down on.
I remember seeing these type of signs 36 years ago at Don Muang Airport arrivals. Back then i even saw the occasional people being told off. I always make it a point to dress in long pants and a shirt when i go to immigration, i believe it does help.