I am one of the few who passes on such info over the R/T, and I get stick for it. For example, I will pass traffic info if I think you might want something to look at or if I have had to put on what you might think is an onerous restriction due to traffic. If, after such a restriction, you see another aircraft which I have pointed out whizzing across your nose 1000ft above or below, I hope that will help in your appreciation of the bigger picture. But as I say, I am in the minority. Most take the view: "IFR separation, no need to pass traffic" and of course ultimately they are right. But it does little to expand our mutual understanding.
Another thing while we are talking about trust and communication:
Be a pilot, not a computer operator.
Two examples:
1) Traffic at FL380 for LL. "London, XXX request descent" So you amend your plan to fit that request in. Then they sit there for another 15nm before descending, screwing up the amended plan. I know that what is happening is that the autopilot prompts you to reset level in MCP or something 15 miles before TOD, and then it follows the VNAV profile. But a little piloting appreciation will show that if you ask for descent we expect you to descend now.
2) Heard on N866 the other day:
"Jersey, XXX request descent" (probably prompted by the same event as above).
"XXX, company traffic opposite direction 1000ft below, descent in 10 miles"
"Roger, we have him on TCAS".
Not transmitted, but I and others immediately think: "Well why the **** did you ask, then?".
