thank you for pointing that out. but sometimes, some people interchange these terminologies... so i just want to brought up also if its an extension already, is it possible to change reason of stay...i posted this question in thaivisa forum website and got few answers. i might post this question here some other time. thank you :)
its been ages since i did my last border hop. Things change. I would say that it depends on the Thai border immigration if they will let them in or not. 1 factor is if they have a lot stamps ins/outs already. but as you mentioned, its their first border hop, so i think there will be no problem. Enjoy the trip and drive safely.
also watch out for people there trying to offer "assistance"... never give your passport to them if you are doing the border hop yourself. if you go with the agency, its ok.
hour drive from bangkok to border. make sure to bring your driver's license, car registration, passport as there are checkpoints on the way to the border... be reminded that you can not cross the border unless you have a re-entry permit. You friends need to stamp out from the Thai border and cross the other side and stamp in and out also from the cambodian side. (sometimes, even filipinos are being asked to pay "visa" for entering cambodia for short time)... then they need to be stamped in at the thai border again... the whole process will take 1 hour depends on how long the que is