The 'just self report and fill in the online form and they'll leave you alone' is simply not true for everyone. This is a myth alikened to that of the detector vans.
For some people, this action triggers constant 'Has anything changed?' letters with warnings that they may still be inadvertently watching live TV or contravening the terms of not needing a licence like watching Iplayer and the harassment starts for the first time once they identify themselves formally to the BBC and announce that they ought to not to be paying. For others the second it lapses they are harassed. You have told them you know what the rules are and so they feel it's easier to catch you breaking them having previously been aware of them.
I was very aggressively and repeatedly (3 x in two weeks) doorstepped by a man who was quite intimidating, just a few months of not renewing the declaration. This happened about 5 years ago. At the time I was sick, struggling with work and had no money and something like just £12 to live on weekly after bills. It was one of the worst and most stressful periods of my life. I explained this, but the inspector didn't give a toss and tried to force me into agreeing and signing up to a weekly direct debit. In fact he did put the fear of court into me so that I did sign up because he refused to go away, but I later phoned, complained and canceled which was long drama in itself although I later got an apology.
What people don't realise is when they come, unless you shut the door immediately, they treat any attempt to refuse them entry as default for watching live TV and start the threats to send you to court right there on the doorstep. The awful man who came to me said: if you're not prepared to let me in I have to assume you are watching live TV and watching Iplayer.
My mistake was admitting I still had a SmartTV with iplayer capability (built in) It didn't matter after that what I said. Truthfully the TV was a Panasonic, and they no longer put out system updates meaning Iplayer didn't even work (which is why I even mentioned it, thinking that would be sufficient proof to leave me alone). But he simply stated that he couldn't assess the veracity of what I said without letting him in. He even put his foot in the doorway to prevent me closing it. Which being a non-confrontational person I would have found difficult to do anyway.
TV was off the majority of days with me only watching the odd pre-recorded American based program - usually Pickers - but this was turned against me also as it meant I must have an outside aeriel and therefore be watching live TV.
Now I currently don't have a TV, having borrowed it to someone who hasn't returned it and I haven't pushed for it back. I don't miss it at all. I have Amazon Prime and barely watch anything on that either, at best 3 programs a year. I just like the quick deliveries.
This time having been burned previously, I simply let the letters come then bin. No drama about it. Saving myself from drama actually.