There is no bridge in Buengkan. He can go to Nong Kai. That's about 2-2.5 hours in a minivan. The bridge closes at 10pm i believe. Dont know what time it opens in the morning. Maybe 6 or 7.
Having been there several times I saw that its the same guys standing there each time.. They must make a decent living. Only takes a couple of fools a day to make a great salary ;)
Maybe they thought you used a "visa agent" (the scammers out front offering to speed you thru everything for 1000-2000 bath).. They have a big sign saying there is no visa agent service accepted.
The only advantage being if there are loads of people already when they open, you can get a better queue number by not using time to fill out forms etc