I dont think that is a practice widely used and would be frowned upon by most IMCR/IR pilots.
I do not know many IMCR/IR pilots who would oppose compulsory Transponders for powered aircraft in IMC.
Maybe not, but until it's mandated, there are people who can and do operate without transponders in IMC. Maybe not the majority but they do exist.
As a Heavy Iron pilot you also know that many destinations are OCAS and with NO RAS even for A320 737s etc
Just to be 100% clear, there is no RAS for any traffic in the UK. It's a Traffic Service or a Deconfliction Service, and has been for a few months.