BTW the grid can only detect big mining farms that use a lot of electricity which is abnormal not all miners that are smaller and use far less electricity which is not so different from normal usage.
the grid can detect smaller amounts.
its not like there is only 1 power meter at the power plant. what you will find should you seek out around your neighbourhood is electric relay stations. yep each neighbourhood has one somewhere.
ontop of this houses and buildings have their own meters which allow power companies to charge users for the electric they use.
most countries do not care about a hobby miner with 1 rig..
what they do care is if someone is trying to be a farm with dozens to hundreds of rigs using the residential circuit
power plants in most countries do not care about mega farms. as long as the mega farms are buying electric allotments from the EXCESS capacity, and not the paid capacity that goes to industry/residential