Sammy Hagar's gotta be pissed -- a Cabo Wabo restaurant that doesn't serve tequila sounds like a ripoff, and that's exactly what it is ... according to a lawsuit filed by Sammy's old brand.
Campari America -- which bought the rocker's chain of nightclubs, restaurants and tequila -- says 2 San Diego-based restaurants ripped off its trademark name to confuse customers looking for the real deal.
According to docs, both Cabo Wabo Grill and Cabo Wabo Grill 2 -- opened in 2010 and 2013 -- knowingly used the name's established popularity to attract patrons. What's worse, Campari says the joints don't have proper licences to serve liquor ... so they can't even sell Cabo Wabo tequila shots!
Campari is demanding the grill owners change the names and fork over some dough for damages. We reached out to the restaurant owners ... but no word back.