back when visa exempt entries were limited to 2 entries at land borders (before the 60 day visa exempt policy), the government had carved out an exemption for citizens of neighbouring countries (I know about Laos and Malaysia, not sure about Cambodia and Myanmar). Still created issues for expats, though.
your visa history with the ED is risky. Moreover, a lot of the data comes from before Nong Khai was a lot more relaxed - they're really more strict now. Why don't you get an agent, or fly in with safe entry?
For an immigration officer to conclude that a day tripper is abusing the visa exemption scheme is quite ridiculous, especially since you probably have residency in Laos. At least if they deny entry, all you got to do is just turn around and go back home.