How does the Khlong Yai/Cham Yaem border compare for US passport holders seeking a 30-day visa exempt entry after multiple entries into Thailand?

I've read that Tod Daniels recommends the Sadao and Nong Khai borders for someone with a lot of entries over the last year, looking to enter with a 30-day visa exempt. How does the khlong yai/ Cham Yaem border compare?? US passport and no land border crossings this calendar year, but was warned at DMK last month that it would be my last entry. Also, was this just a threat from the officer as I know they are stiff at DMK, or can they really flag you in the system?? Poipet is my first choice for ease of access if you tell me that they didn't actually flag/note me in the system...

Also, if i did get denied, how is that done? I assume i'd need a new passport, but is there a certain amount of time i'd have to wait before being allowed back? Thanks in advance.