What often puzzles me is why many recorder players seem so set against the tin whistle/flageolet

In one word - snobbery. You'd be amazed at just how much snobbery there is in certain quarters of the recorder world. The recorder is a wonderful instrument and just as demanding as any other instrument, but some people seem to have an inferiority complex about it which I put down to its image as something you teach to children till they are big enough to learn a "proper instrument".

There is also the factor of fingerings being nearly the same. When I first picked up the tin whistle I often found myself using recorder fingerings for F# and Cnat. You can just about get away with it for C if it's a quick passing note but not for F#. The problem is the fingerings are nearly but not quite the same. The same applies to the wooden flute and the Boehm system flute. Interestingly I never found the same confusion between fingerings when learning the wooden flute - I put it down to the different positions you hold the two instruments. I took the easy way out and now rarely play the whistle though I have a few in different keys.