Was a common statement when I did the SDI solo diver "workshop". The practical component of this comprised of me having to demonstrate that I can solo dive with the instructor providing "problems". It was one of the most enjoyable training I've ever done with a load of challenges with entanglement, blindfolded, loosing kit (a fin "fell" off), masses of gas leakages (shutdowns, etc.), triaging problems (entanglement is less important than the air gunning/shutdown), doing a blindfolded ascent using an SMB with a stop at 5m/16ft, etc.Hunh? Where did that come from?
I did this course after my normoxic trimix (60m/200ft), so was nicely dived up and well practised.
The Solo Diver is a recreational certification, not technical, so doesn't cover decompression, etc.
As far as I am concerned, solo diving requires the tech diver's mentality; redundancy, planning, etc. Of course you can do the solo diver course as a recreational diver, but you must be competent in the water and especially with redundant gas switching.
The only time I've actually used the qualification is a few times in Wraysbury (lake beside Heathrow airport). None of the PADI community that I've encountered recognise it as such because the buddy system is so ingrained into their ethos.