@James *******
It's proper to refer to it as the Aranyaprathet-Poipet or simply Aranyaprathet border since the problem isn't in Poipet, unless you're Indian, Nigerian or Indonesian or from another similar country. Poipet immigration regularly denies entry to citizens of these countries and several others in South Asia and Africa.
However, on the Thai side, the main problem is with upstairs immigration for any foreigner regardless of nationality (except Cambodians, unless they're spending too much time in Thailand) who aren't in Thailand on a long term visa...or they're a tourist who is simply spending 2 weeks in Thailand then going home.
The vehicle entry point is no problem if you're a DTV holder, on a multiple entry non immigrant visa or even as a tourist for the most part, as long as you're the driver as only drivers can stamp in there.