Is there any foreseeable issue with using multiple passports to exit and re-enter Thailand?
For example, once I've exceeded the 2 annual land borders, can I simply exit at a border and then return on a second passport?
TLDR : Answer Summary
It is generally not allowed to switch between multiple passports when exiting and re-entering Thailand at land borders. You must leave Thailand using the same passport you used to enter. The only exception to switch passports is when traveling by air; that way, you can use a different passport for re-entry. Additionally, be aware that other countries you visit, such as Myanmar, may also require you to exit using the same passport with which you entered.