PROBABLY THE BEST?

PROBABLY THE BEST ??

So far I have seen three marketing campaigns.

Antwerp – ‘Belgaufra (belgian wafels). Probably the best since 1950’
Sarajevo – ‘Carlsberg. Probably the best beer in the world’
Berlin – ‘Ben and Jerry’s. Probably the best ice cream in the world’

What’s with the ‘probably’??

I get that it ‘probably’ has something to do with legalities, but to me it sounds funny, either it is or it isn’t. Or, it ‘probably’ is!