I just arrived in Thailand with my non b multi (1 year). Immigration stamped me in for 30 days exemption so I had to go back and they corrected it to 90 days (he even showed me the date in the computer) but what I want to know is if he forgot to stamp "used" on my visa. They have precisely did that in all my past visas. Do they stamp used in this visa or not? Do I need to go to immigration and really check he I am my non b visa or not?
TLDR : Answer Summary
The user inquired whether their Non-B Multiple Entry Visa would receive a 'used' stamp after entering Thailand, as they noticed this on previous visas. Commenters clarified that for a Multiple Entry Visa, such a stamp is not applied. Instead, the visa remains valid until the specified expiration date, indicating that it has not been used until a border crossing is made, verified by checking the entries noted on the visa.