Are We Getting Our 100%?

[barmisspah?]

I did once ask the landlord who served me a pint with a full inch head on it to place it on a shelf for 10 minutes and see how much beer I actually got.
Sure enough once settled it was far short of the top of the glass. He claimed it was evaporation due to the heat. 

He then asked me to leave 

You should have said "can you fit a whiskey in there please " he will always say yes....then you reply "well fill the bastard up ".........Simples.........

When the children were small, I worked in the pub next door & always gave good measure (waits for smutty remark). If the beer was playing up I would tell the customer to take a sip & then top it up. Before I could say this to one of the regulars one day, trying to be clever he came out with the 'Can you put a whisky in that', I replied 'sorry, no' - he didn't do it again.