Mae Sot-Myawaddy border crossing: Confirmed that non-Thai foreign nationals can't cross at present. Was told by one of the Burmese nationals who works for Thai immigration that the Burmese side stopped allowing us across roughly on or shortly after April 7, when major skirmishes close to Myawaddy caused thousands of locals to briefly flee across to the Thai side.
Strangely, the two Thai customs officials i initally spoke with didn't know this and directed me first to the office where Thai immigration works on the outbound side but because both officials were busy stamping border passes, they finally led me to the inbound side where i was able to receive confirmation from said Burmese immigration helper.
Was also told that contrary to what I had previously thought- foreigners were in fact allowed to spend the day in Myawaddy township just like Thais, as long as they returned back to the bridge to pick up their passports before 6pm Myanmar time. So it wasn't true that you were forced to turn around immediately and couldn't enter town.
This confirms what my Burmese colleague told me when he contacted an official there, who said foreigers are welcome to travel around Myawaddy, just can't leave town and must return to Thailand the same day. Obviously said official wasn't made aware that Myanmar immigration quietly decided to ban us altogether a few weeks ago.
Otherwise, why wouldn't Burmese immigration allow that system now? They could make money off of us by charging for the stamp and send us straight back. So clearly right now they feel it's too dangerous to allow us across even just to their side of the bridge.
Strangely, they don't believe it's too dangerous for Thais to come across for the day. On the other hand, obviously Thais have a need to load/offload goods and conduct trade related activities, which doesn't apply to third country nationals.
Hoping that the bridge will reopen to us foreigners soon, but I'm not getting my hopes up.
TLDR : Answer Summary
As of now, non-Thai foreign nationals are not able to cross the Mae Sot-Myawaddy border due to recent security concerns after armed skirmishes near Myawaddy. Although there was some belief that foreigners could temporarily enter Myawaddy township and return the same day, recent developments indicate a complete ban on their entry. Thai customs officials were initially unaware of this restriction, but confirmation came from a local Burmese immigration helper. The situation is influenced by safety perceptions and the need for trade activity, particularly for Thai nationals.
