When we used to do HA work I found a few leccy meters bypassed and tenants stealing leccy from the communal supply.
If I couldn't gain access to do a gas check I used to check the leccy meter to see if there was a big debt on it, if there was it generally meant the tenant had done a runner. I checked one and there was a big debt built up and it struck me that the doorbell had worked and it was through a transformer in the consumer unit. This prompted me to look closer and the meter had been bypassed with a piece of meter tail which had about an inch of bare wire showing either end. These meters were in communal cupboards in the hallway and were frequently left unlocked. If someone opened the cupboard they could easily have got a shock. I was particularly peed off with this tenant because this was now the fourth failed appointment so I reported this to the leccy board as a safety issue as well as theft. Because of the danger I hung around for the team to turn up to make it safe. They arrived with a guy from revenue protection, took out the main fuse and removed the meter, complete with bypass, using a pair of bolt croppers. The following evening the guy from revenue protection called round to see me with a bottle of wine.
In the same block there was tenant who was a real PITA. Whilst working in the hallway outside his flat I noticed an extension lead coming from under his door plugged into the cleaners socket. I needed power so I unplugged the lead and "accidentally" forgot to plug it back in. Apparently he was running his freezer from that lead and he lost a freezer full of food. Next time I visited the lead was there again so the HA had key switches fitted to prevent tenants using the sockets in the communal hallways.