if you're referring to the RW4U's interview with an MFA spokesperson, they were discussing unlimited entries on the Destination Thailand Visa, not visa-exempt.
Because the DTV is new, any suggestions are informed guesses at best, but from what some reports suggest, a fair few embassies and consulates are asking for proof of residency. But apparently Vientiane isn't - you'd have to check for each individual embassy and consulate.