I never was a dub.
As far as I can see, all 'field service' achieves is pissing off the dubs who have to do it, and, more importantly, exposing dubs to things that may (just may) question their faith.
Two examples : a few months ago a young dub (about 18?) and a younger companion (about 12?) called on my son's house whilst he and I were in the garage fiddling with my motorbike. I'd just read (here on JWN, of course!) a recent mag which re-inforced JW teaching that Adam (aka mankind) was created 6,000 years ago. So, we had a discussion (there had been a recent BBC programme about an excavated house, at least 10,000 years old, on the NW coast of England). I gave him a note of the link to the programme. Will he check it? Who knows.
Second, I had a 'panic' phone call' from my daughter a couple of weeks ago. Dubs were on her estate. She (knowing and sharing my views) wanted a quick question to ask them. There were four, two late middle-age ladies, an old guy and a young aggressive man. They gave the usual crap, the young guy in the lead, and the introductory question about the 'sad state of the world today'. She asked the young guy if he had access to the internet. He said he did, so she told him to google 'Candace Conti' - then come back and try to explain that. (She had my young grandchild in her arms but warned him that if he tried to take a step over the threshold she'd lay him out (which she would)).
If (and I realise that's this a big 'if') the dubs who are going door-to-door report back their true experiences, how long can the WTBTS let this continue?