Genghis,
I entirely agree, I only make an initial suggestion (if I think of one when testing) when delivering the bad news, then leave the designers to get on with it (unless they have any questions etc). I try to keep a balance between the ‘tester separation’ and the ‘Teamwork’ ideas, as I don’t want to get to estranged from the rest of the process, but don’t want to ‘contaminate’ the test side either.
In my previous incarnation (avionics integration and test), my team was merged with the design team and put under one manager, with idea being that everyone gets to do a bit of everything (I think the designers were bored rigid with their part). We pointed out the flaw in this idea, but were merged anyway, luckily everyone kept doing what they had been before anyway (but we had the same manager and were co-located, which was a good thing), so there wasn’t a problem.
I would also like to stress (as others have before me) that teamwork is essential, my original post probably didn’t mention this too strongly (concentrating on the ‘delivering bad news’ part), and comes across a bit ‘them and us’. It can be difficult, especially with large firms being spread out, or two or more firms involved in the project. Currently I am in my office, which is handily located over 800 km from the aircraft, which needs an hour or so flight and a 2.5 hour drive to get to. Previously I worked on a project where the two firms were in different countries, which added the extra obstacles of differing outlook, culture and, of course, language. However, all of these things can be overcome (or minimised) with a bit of effort, and, of course, teamwork.