Night IMC - I recall reading more than once that some of the most demanding of all flying we do is night IMC. If you read the NTSB reports it is indeed noteworthy how many accidents occur at night in IMC. Of course in Europe so little night IMC is flown that the number of accidents are insignificant.
Formation - some would have you believe this accounts for the highest number of accidents. I am not sure whether the evidence supports that assertion. As has been discussed on another thread there are of course variation of formation from flying in very well spaced company, to tactical and close formation.
Tail wheel in to farm strips - I guess I mentioned this one not so much with an eye on the tail wheel in particular, but because it is tail wheel aircraft that are more likely to go into the shortest strips and therefore press the boundaries of what is possible. While usually the accidents aren’t serious, they do seem to account for a fair number. Perhaps that is just because pilots are “pushing” the boundaries, or because conditions are less controlled (usually the strips are un- managed and inevitably grass).
Risk can be managed, although I am not sure how you manage the risk of night flying with one engine. If the engine stops there is a large amount of unmanageable luck involved.
Only a fool doesn’t try and manage the risk (albeit there are plenty of fools around). We might assume that most pilots who fly night IMC have therefore taken what steps they consider necessary to best manage the risk. However the accident rate is high. This might suggest it is one of the most “demanding” forms flying takes. However, on the other hand so is aerobatics, but interestingly the accident rate is very low. I wonder if this is because the pilots manage the risk better or because the risk is inherently less?