Agreed but then you'd have to have an instructor with an IR and an IFR aircraft to do it in legally.
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Yes, and this is the problem. To get training value out of it you really need to do inadvertent IMC in cloud, and not in VMC with foggles. I've had experienced pilots but with newly minted IR, where for the whole of their IFR training never went close to a cloud, on day 1 of the IFR job as soon as they get into cloud for the first time things are totally out of control within about 30 seconds.