During my CPL training, my instructor had me fly in clouds (the time in clouds being part of the 10 hours I had to fly without external references.)
Was it bad practice to your opinion?
I don't know whether he had undertaken the IRI training or not, but assuming he had not, would have it been illegal?
I think that Flying without external reference is also part of the PPL syllabus. Would you undertake that part of the training in real clouds without being an IRI? Would you think it's a bad practice?