Having had two (mountain) bikes stolen (from a locked garage) last year, I welcome the Police stopping people who look "wrong" on a particular bike.
Unfortunately, from the discussions I had with the Police at the time, the MTB (or MTB style bike) is the one most likely to be stolen, as this is what there is general demand for. This tallied, as my BMX and commuter bike - also in the garage at the time - were untouched!!
If this means that I can be stopped occassionally while on my MTB and not wearing MTB type clothing, I would have no problems. I go to the football, and are regularly "frisked" on the way in. Do I mind? No, because I can see the bigger picture of why it is done, and I have nothing to hide.
The sooner cycle theives - and equally people who are willing to buy these bikes who in reality must be suspicious of a "bargain" - actually believe there is a chance of being caught the better for the decent cyclist who is concerned about cycle security, and increasing insurance premiums.
However, as Police local to me seem to have had little success with none illuminated cyclists on an evening (except for occassional "crack downs" which seem more of a publicity stunt by the statistics generated), I can't see the position getting better quickly.
As an aside, a few years ago, my workplace was broken into during the early hours of the morning. Afterwards, it transpired that the local constabulary had driven past a young man carrying a computer base unit down the streen a few hundred yards away, but so as not to delay arrival at the crime scene hadn't stopped to enquire what he was doing!!