You can get stuck at land crossings if the officers are not aware and dont understand the visa. It took me more than an hour on one occassion. This is probably due to the fact that some officers at land crossings havent seen the visa. However once they finally understand the visa they will quickly process you. On some occasions the head duty officer photgraphed the visa presummably to show her staff.
Following the rules is good. But not recognizing legitimite visas and arroangance is not good. BTW my letters confiem who I am and that I am following the rules. Sometimes when you roll up at Padang Besar at 9.30pm with a legitmate visa and they tell you it is expired, it gets very frustrating. There is a lot going on there. I have been going across that border 3 times a week since 2001
One time I went through with a Non OAwith multiple reentry permit the IO refused to recognize it and after 2 hours stamped me in as entry without visa. It took 2 hours. I went to the immigration at Hat yai airport and they corrected the error. They just mess up things
I just object to the arrogance and rudiness and even dihonesty where they dont recognise your visa. I have my act together dont worry. I also carry a personal letter from the Governor of Songkhla and head of the 4th Army, which i only use after the shit I am given.