Now I'm not one of those pub-goers that screams "Trading Standards" at every minor infraction of some petty rule but this poster did catch my eye. It seems to be saying Guinness, John Smiths Extra Smooth and Strongbow are lagers.
Evidence of the cheapo shoddiness rather than an attempt to deceive I would think.
Yes, observant readers, this does mean I've set foot in a Wetherspoons again. All in the line of duty. I'm sorry.