I used to work for British gas and they were constantly reporting people but only fair size operations.
We could see when there was a great voltage draw this is caused by the igniters that spark the discharge lamps, there is a great very unique draw to ignite the discharge lamp which we can see, when the bulb is first ignited, its only when they reach full brightness this then drops. Its a very, very unique power draw nothing else like it. LEDS are completely different but still unique, the transformers instead step down the voltage which we can also tell, but a great deal of people use LED for down lighting in their ceilings but these only draw 100 / 300w in houses. We can even tell when people open their fridge due to the power it takes to re-refrigerate, invasion of privacy I know!
The best way to hide it is use Tesla modules to charge and discharge the electricity, you can even charge Tesla modules at charging stations if you want to be super under the radar but a advanced charging system would need to be setup to charge at the 50kw charging speeds, no electrical company will report high usage its only if they see a correlation at certain times of the day lights on / off as people could have 1 electrical heater per room! Thats 3kw, if you have 10 rooms thats 30kw per hour 720kw per day! Some people just dont realise how much a electrical heater costs in power.
Ps What ever you do DO NOT Steal the power!!!!
Thats the biggest reason people got caught, its easy to pin point the house that is stealing power even if you are temporally connecting and disconnecting the meter.
Ps dont tell them I told you guys.