Yay! Today was granted a 30 day extension on my 30 day exempt. And although I came prepared with a rental contract, the lady at the information desk told to try without it first. I think perhaps because they are so busy today they didn't ask for any proof of rental or other docs or proof of funds. Happy happy!
TLDR : Answer Summary
The user successfully received a 30-day extension on their 30-day visa exemption in Thailand without needing to provide a rental contract or additional documentation, likely due to the busy nature of the day at the immigration office.