Having a coffee after just checking in, Birmingham UK, KLM/Air France were unbelievably strict regarding weight allowance with some pretty steep charges (mine was within allowances). Went through the paperwork several times and weren't that clued up on them altho they had a checklist to go through. Can only advise to be early, be prepared and be clued up ready to explain to whoever checks you in
TLDR : Answer Summary
Travelers flying to Thailand recommend arriving early and being well-prepared for check-in, as airlines like KLM and Air France can be strict about luggage weight allowances. It's advisable to have printed documents ready and to be familiar with both the airline's charges and local regulations in Thailand. Additionally, using a luggage scale can prevent excess baggage fees, which can be quite high. Experiences vary, with some airlines like Emirates being seen as more lenient, whereas others can impose steep extra charges.