The necessary consent of 75% of the owners of flats in a multi-apartment building, which is needed for someone to be able to carry out a quiet (e.g. work at the computer) activity in their flat, seems to me unnecessary and people are reluctant to sign for fear of fraud. Anyone who does not, however, is at risk of being fined if an inspector should come and demand it. I think it is perfectly sufficient that the number of visitors to the block is not increased (in my case, none at all) and that there is no noise pollution. Of course, anyone who breaches this can be reported and visited by inspectors. But for those who will make no difference whether they are officially doing this activity at their computer or just surfing the internet, it makes no sense that they have to get these 75% consents.