Exactly the same for me. Come to that, nor have I personally ever come across a situation in which anyone has come to harm as a result of pulling such a CU fuse whilst significant current was flowing through it (although the fuse holder may have been somewhat damaged).As I said in a later response I think is down to the individuals risk aversion. The examples of possibilities you suggest are not things I have ever come across in 50 years but I am not saying they don't exist ...
I don't think it can be taken to say anything about how 'competent' the electrician is (to undertake work satisfactorily) but it has to be remembered that this is a DIY forum, and that people reading about what an electrician has done might take that to mean that there is no potential problem in doing the same. I wouldn't dare to mention here some of the ('dangerous') things I've done in my time, but always will a full understanding of the risks and a belief that I was doing what was necessary in order to mitigate them!!, what does concern me is that some of the replies are possibly reinforceing the doubt the poster seems to have in the competence of his electrician. That is the way it reads to me anyway.
Kind Regards, John