@Giorgio *****
it’s not your visa they are checking, it’s your name and your passport number which is printed on your Thai licence, they have to record it in the hotel register, this register is what the police check when they go around hotels, they are supposed to reference the registered guest against their wanted persons on the immigration wanted list.
Yes some hotels request passport, however the majority do not, also travelling with a Thai Partner they can check in using their ID card, 99 percent of the time the hotel will not ask for foreigner passport ect, I know because I have done this for years, once my passport was lost, so my partner used her ID to check into hotel, no questions asked, from that time on I always asked her to check in and buy bus tickets, only once in 12 years a hotel said they needed my ID and requested my passport, as usually my partners ID was enough, I supplied my Thai Drivers licence pointing out my passport number was on it. A friend of mine from America also uses some ID, can’t recall what it is exactly, however it is photo ID / miniature passport data page with passport number, I have travelled with him and he just shows it to check in, and me, no passport just Lao girlfriend booking our room 🤣🤣🤣