This whole, or should that be hole?, scenario grows from the user wanting the MWL to stand out so as to remind them to check vm. This makes me think the solid light is on so much that the effect of it has worn off. The user has grown de-sensitized by the practice of ignoring it. It's their own fualt. I would suggest a screen pop on the PC. Surley that would not be work .... No, eventually that would wear off as well
Better yet, put a stop to it now, take a stand, stop enabling this person, just say no. Looking very stern and in your best Jean-Luc Picard voice proclaim "This stops here and now!" If this does not work flail yer arms about like an angry chimp... but I digress ...
Try this: I do not have a technical solution to your management problem.
Richard
The unexamined life is not worth living; Socrates