There are often free exams for different things. A few months ago it was free weight checks and diet advice. At the moment my vet is offering free kennel cough jabs for dogs.
It's a good way to get folks to bring in their animals and register as patients... and while they are having free check ups for this, that and the other the vets will grab the chance to flog them something esle like flea treatments and wormers. Cynical moo, aren't I?