I like to give and receive advanced warning that something different may happen.
The utility cyclist wrote:My view is you shouldn't be calling out at all, in exactly the same way when using a bell for passing pedestrians .........
If it's very quite and I'm cycling along minding my own business and not checking my mirrors when suddenly something 3'-4' taller than me suddenly appears in the corner of my vision from behind with no warning then I tend to jump because of the sudden shock.
If I had a bit of warning they were there then I'd stay in my very relaxed state.
As for giving a warning, I do it again because a recumbent trike is so different from a bike.
On any road/path due to where the wheels are, I ride about 18" wider than a bike.
So even with the safest overtake, I've got that much less wobble room.
So I think giving a warning that something different is coming passed makes it that much safer.
It is ALWAYS incumbent on the overtaker to make sure it is safe to overtake, if you as the overtaker are passing in a safe manner with enough space taking into account potential hazards and situations that might crop up - like junctions, parked cars, road defects etc, then there is zero need to warn anyone.
35 years I've been cycling this way, never warned anyone that I was passing, never needed to because I accounted for 99.9999% of all eventualities (a frozen block of urine falling from a jet or a golden eagle dive bombing from above are obvious scenarios I won't be thinking of), when I'm being passed then I don't need you to warn me, would you do that when rotating in a chain gang, no you wouldn't, mainly because you have an element of trust and understanding.
So someone you do not know, don't know their experience level, their thinking towards hazards, what they are going to do next -a right turn for instance or change line for that road defect you've not seen) how they might react to you shouting out that they might not even hear anyway (wind noise or deafness or even earbuds) then you MUST always take account and either hold back/change speed and ride wide.
Sorry but I couldn't disagree with this nonsense of calling out to people and wanting people to call out to you even if one can be heard or you hear them, it's simply not needed, it's totally unnecessary if you are riding safe with respect to others and the prevailing conditions/environment.