What exactly is the requirement to get a warrant for? Why do we require the police to get warrants? As far as I can tell, its to stop the police abusing their search powers. I don't think cutting utilities first is an indicator that the police are not abusing their power, so why does it negate the need for a warrant?
Why not extend this idea and cut off people's water or electricity. They'll never need warrants ever again for anything.
This kind of thing might work once, but it endangers the lives of field service personnel. Did your internet go out just before your multi-million dollar drug ring got busted? Well, I don't fancy the chances of that technician (who's face is on your gate security footage) surviving very long, even if he had nothing to do with it.
Get a warrant. Do it properly.