Well you can all pick apart my sweeping turn of phrase
but the fact is that most GA traffic does crawl low down, below 2000ft, and this is evident when flying under an RIS - most reported targets that one does spot (which is not a large %) turn out to be well below.
So anybody looking to minimise the chances of a contact should fly high.
And if one can get VMC on top, there is almost nothing there and one can fly for hours without a single GA contact. Much as is the case on airways flights especially outside the UK.
Instrument capable / instrument legal pilots don't sit in cloud. They use their privileges to remain VMC. Pilots who spend serious time in cloud will be mostly the UK IMC Rated pilots who are zooming around under the base of CAS and there aren't many of them around.