An F-4 nav once told me that, back in Cold War times, he'd been on a detachment which was visiting a Luftwaffe base. During the evening, some of them thought that it would be fun to sing "The Flag" - so they did. Much tutting and muttering from their hosts, most of whom promptly left the bar.
The RAF boss was mentally composing his speech for the Axminster Shuffle which he thought would inevitably be coming his way once back in Blighty, when the door crashed open. In marched the Luftwaffe mates, loudly singing the original version. Once they'd finished, their Boss said "If you Brits must sing that song, at least get the words right!". Much beer and bonhomie then flowed!