Glueman told us:

For similar reasons I always go for the pint glass option rather than the more popular half pint'er at beer festivals. Although the 1/2 is clearly marked the over-worked girls behind the bar never fail to give a larger measure and I've often had shorter pints in city boozers than a festival 'half'.

Am I missing something here?

Seems to me, re- and re-reading the above, you're trying to avoid getting a bit more beer for your money. You say that 1/2 pint in those circumstances usually comes out more like let's say 5/8 pint. Is that bad?

Dave Oesterreich