are you 100% sure or going of something you read, do you know someone who arrived today after 4pm that actually has there passport stamped for 60 days visa exempt?
Yes 30 day exempt than 30 day extension at kamphaeng phet immigration office had till 2nd july but left on the 26th, got pulled up at Suvarnabhumi Airport, had to go to side counter and show receipt, but had 2 receipts 1 for extension and 1 for fine for not notification of residency, not really sure which one they were interested in , but stamped passport and left no problem.
You don't require anything for that amount of time , on arrival you will be given 30 days visa exemption, nothing is required just turn up with your passport.