I think the important thing is for a pilot to know his own personal limits and those of the aircraft and also the legal requirements and to stick by them.
Any pilot can get caught out by a bit of cloud; suitable training can teach how to safely deal with it. I'm a believer that exposure to the situation in a controlled environment i.e. with an instructor, within the law, is the best way to keep a pilot safe for the future.
Unfortunately, common sense cannot be taught. For example, not so long ago I had a close encounter with a single engined helicopter (R-44), whilst we were flying IMC at 2400ft under a RIS. The R-44 was presumably being flown illegally because he was at an estimated 2300ft in solid IMC, not squawking and not talking, crossing a commonly used route in and out of the Heathrow zone. We were advised by Heathrow Radar of his presence but wrongly assumed, because of the weather and other circumstances, that he would be below the 1500 foot overcast. I don't think he saw us, but we saw him. I am fairly certain which aircraft it was. I hope the pilot isn't doing this on a regular basis or we might be having another "statistic" in the not-too distant future and if I see it again I will definitely be reporting it.