What are your feelings about introducing an operations-research tag?
I was tempted of introducing it but as it OR is also covered by combinatorial-optimization or graph-theory and maybe also other fields of mathematics, I am not sure whether such a tag would be considered "superfluous".
What would speak in favor of such a tag would be to indicate the relation to, resp. motivation by practical problems when used in addition to already existing tags to alleviate searching for (solutions to) practical problems.
Edit: the operations-research tag has been created by the OP.