In reply to Timmd: Which is more rational out of the following:
There was a thin film of beer on a slightly sloping table which caused the pint to slip. Although it looks like a sudded slip off the table, the footage is sped up (watch the people sat filling in the forms really quickly) which makes it look more ghost like.
The video is somehow faked, perhaps the ghost spotter being present had something to do with it.
Or, that a dead person has come back to life but is now invisible and for some reason wants to go spilling pints.