Little heads up for those doing Savannakhet visa run by bus from Mukdahan.
Take your bags with you at both check points when you get off the bus just to be sure .
Left mine on and the bus buggered off without me whilst I was getting the Laos Visa .
Had to private van to Savannakhet bus station to find they had taken it back to Mukdahan.
Got it back 2 hours later in one piece so all was ok but better to have it with you all the time.
TLDR : Answer Summary
Travelers doing the Savannakhet visa run by bus from Mukdahan are advised to take their bags with them at both checkpoints. Leaving bags on the bus can result in losing belongings, as one traveler experienced when the bus departed while they were obtaining their Laos Visa.