Visa Runs often go like this... Go to the Thai Consular Services office in the other country. At about 8:30 am get in a queue... Then after 9:00 am apply with the application form for the Visa you want to buy... The Applications window will close at 11:00 am
The next day after 2:00 pm you go back to the same office to collect your passport with the new Visa sticker or stamp in it
A border run or border bounce means you just go through border checkpoints on both sides of the border to Exit and near immediately return to Thailand after getting Exit and Reentry Stamps
I've read this overnight policy is related to Thailand'a response to host countries, where the Thai Embassy/Consular services were located, feeling a bit left out of the money stream... No overnight stays means no money spent on lodgings, less on in country, transportation, less spent on food, souvineers, general goods, etc.