If we avoided every car which has issues/have had issues - we would never stock anything.
I generally (and respectfully) ignore most warnings providing:
1) Number of keepers is acceptable (including how long last keeper had it)
2) Mileage is sensible
3) Service history is good
4) MOT history looks well with few advisories
5) 2 keys means a lot to me too - it just shows someone has been "good" with the car (IMO).
6) Vendor selling the stuff (i.e. I avoid Supermarket PX's)
I do make sure there is good/excellent margins on any forewarned stuff (DSG, German, Land Rover etc) - that is the key and the biggest point for me.