Rob,
I have certainly witnessed this in Accompong Town. Although there was some current 20 some years ago, there was no reliable current until about 5 years ago. At that time I would estimate only 45-50% of the people using electricity, were paying for it. Now, less than 5% are still using "bridges" and enforcement is getting better at catching those who still practice it.
Even with the remoteness of Accompong Town, the current is on nearly all the time now and the "browning down" effect that was common and caused electrical appliances to go bad is rare to almost non-existent.
I think that JPS has a hard job stopping all the illegal connections but they are putting a lot of effort into stopping what they can.
Peace and Guidance