South Florida restaurants have been doing that for decades. Especially South Beach Miami. They get so many European and South American visitors who don't even consider American-style tipping, so they started adding it automatically. I agree, however, that it should be much more visible, or that waitstaff should clearly state out loud, a suggested tip is already added. But I think that since 90+% of customers are vacationers and not locals, the restaurants don't feel like they are jeopardizing repeat business by not mentioning it.