Could RT be improved by allowing other profiles, e.g. RT_sRGB, to be set as the soft-proof profile in Preferences, hence achieving a more general “gamut warning” rather than just a print profile indication? And rename it in Preferences to “Gamut Warning” rather than “Printer (Soft-Proofing)”.
(Side note - I’m reminded just looking at this that the tool tips for the soft-proof icons refer to output profiles, which of course is not how RT works. I’m guessing that at some point printer profiling was intended to be based around output profiles, and then things moved on.)