Electrical disconnecton sand meter readers

It's not completely wrong, since they write down the meter readings after they cut the line 
However, that's common practice: if you don't for the service, you are not entitled to the service. And if you do not open the door for the person who is responsible to stop the delivery of the service, they have to find other ways to get to the meter.
Better like this than they have to break the door ...

Luckily I've never had any problems regarding this, neither in Malta nor elsewhere, but I can assure you that in Austria, too, the technicians of the power company or the gas company or the water company get into the staircase, basement or wherever the meters are, and disconnect the electricity, or gas, or water. They usually use the key for the postman (postmen do have their own keys to open the front door in many blocks), or ring the neighbour's doorbell.

And in Spain it's similar, there they usually just ring and pretend they're delivering promotional material, or wait for someone to leave the block so they can get in.

I'm not saying I think this is an alright practice, but it's not just a Malta thing.

i have to say its not something i have personally witnessed but I do know others that have witnessed this....  many meter are not accessible by the tenants they are relevant too... only LLs know the answer as to why?

Be warned this happens more than you think = and the reason disconnections happen is explained here and its nit always the tenants fault - Here in this youtube video - Maltas tenants are easy targets and this is the reason why - tenants are invisible https://www.youtube.com/watch?v=zpB21ee3BeY&t=5s