As others have said, interesting thread.
Also interesting is that some of the younger atcos coming in to the job now don't have much knowledge of the lighter end of the aviation spectrum.
I wonder, if someone calls up asking for a routeing west of Canary Warf and giving their a/c type as say a "Beech C23", assuming there is no traffic reason why a clearance should be refused is the atco expected to go back and ask whether the a/c is a single or twin before issueing a clearance?
I tend to fall on the side of Bookworm with this, the pilot is (or at least should be) in the best position to judge whether or not he/she is able to accept a clearance and should only request clearances that are appropriate to the type of a/c they are flying.
It is opening a much wider grey area if we (ATC) start issueing or refusing clearances based on our own opinions of what we think is an acceptable practice and what is not.
Otherwise I wouldn't issue clearances to any single going anywhere after it got dark
WF.