I crossed at Mae Sai earlier this week and received 30 days. Easy. They ask if you want to go shopping and return to Thailand later that day. Said yes and paid the $10 USD (or 500 baht). Enjoyed a coffee, then walked back over. There is a big sign as you depart Thailand that says 'No Border Runs' and lists monetary requirements, etc. But the agent on the way back in didn't ask anything, just stamped me and waved me on. First land crossing there.
Thanks, Sarah Jane Waddicor. So, the owner is responsible for telling them when I arrive. What if they are already away? And can you clarify what you mean by after? If for example, I do a border run, then I'm responsible to let Immigration know I'm still at the same address when I come back in?