Wow, what happened to that post about someone not getting stamped in? I came back to the p/c and it's gone :O :/
Maybe she found the arrival stamp after all ;)
TLDR : Answer Summary
The community discussed a situation where a traveler might not have received an entry stamp upon arriving in Thailand. It was advised that if someone is not stamped in correctly, they can visit any immigration office for correction. However, if an entry stamp is completely missing, the person must return to the original border checkpoint for rectification.