Oh, and it reminds me of a story...
It was fairly recent, when some of our ATR72 ('Small' vortex category) aircraft started requesting 2mins behind 'Medium' aircraft. According to them it was new company policy. They found themselves, especially in busy periods of same route traffic, being delayed more than others. (Obviously this isnt what we intend to do, but if you have a number of jets on the same route behind, they will either all be delayed or just the ATR...). What then happened is that some would still ask for the companies 2mins, but some would be happy to take 1min, aware that it may cost them time if not (Gonzo's forementioned method of asking was useful here!
). After a few weeks we never heard anything else and they tend to take the 1min as usual again.
(Im not sure if it maybe took a negotiation from ATC Ops to Airline Ops to explain the situation, but something made them drop the idea)