The current description of the brainteaser tag is as follows:
A brain teaser is a puzzle that involves thinking in unconventional ways, or one that involves disregarding what seems obvious. It typically requires inductive reasoning rather than deductive.
While the lateral-thinking tag has this in its excerpt:
Puzzles that generally involve thinking in unconventional ways, or overcoming some form of assumed restriction that is not actually present in the problem.
The two tags have nearly identical descriptions, and yet the brainteaser tag is being used for some things that do not involve any lateral thinking at all.
What should be done about this? I propose redefining "brainteaser", but we never came to a conclusion about that the last time this was brought up.
Given that the brainteaser tag has now been burninated, this question has been resolved.