Farkel posted something about this topic in his post on Field Service. I want to make a different point and hence a new thread.
A few years back an elder mentioned this in a public talk. Apparently, he had been giving the same talk at a number of congregations in the circuit. He said something similar to what Farkel mentioned, that is that JW's in FS should not thank householders for their time. Why not? Because it is they who should be thanking the JW's for making the time to come sell them their mags!
I didn't give much heed to this and did my own thing anyway. About 9 months later the CO visited. HE mentioned this thought in particular and the fact that an elder had been spreading this idea. He said that it was a normal British courtesy to thank people for their time and JW's should not be so rude as to not thank people how ever much they thought the "thank you" was not deserved.
Like many rules in the WTS and, in particular, congregations, they are the whim and ideas of individuals who want to press their rules on others. In this case an elder had heard this idea, liked it, and thought everyone else should do the same. The complaints from some had reached the CO and hence his comments on it during his visit.
Are there any other rules your congregations had that had to be adjusted later?
'To avoid criticism, say nothing, do nothing, be nothing'