I agree, and went ahead and created a tag excerpt to this effect (please improve where needed). I've explicitly pointed to linear-system for the alternative.
On a related note: There's about 10 questions tagged linear, which seems in almost all cases to be redundant (although not consistently so; some are tagged linear-systemlinear, others linear-programminglinear). This can be remedied in the same cleanup round, but we might also wish to burninate the tag?
Edit: Actually, before going ahead, we should discuss the target tag: there's both linear-solver (182 questions) and linear-system (21 questions). Do we want to pick one over the other? Make them synonyms? Treat (and document) them as different (e.g., the former is for questions about algorithms or code, the latter for questions about the mathematical properties -- that would be a massive effort, though)?
Edit 2: Thinking about this, I'd propose to deprecate linear-system in favor of linear-solver: Most questions with the former have both tags anyway, and the few that are not about solvers can be retagged as matrix.
Edit 3: I've completed retagging all (in my opinion) mistagged questions with matrix-equations. I can start retagging linear, but I'd prefer if a moderator burninate (i.e., delete and blacklist) the tag instead.