Places that are restaurants by evening and dance bars by night are always a pain. Even loading in can be a hassle if a large group has moved tables around for themselves and blocks access to the stage. I always go to the staff, doorman, maitre'd or manager if I can find them and explain that the band needs access or that tables X are where the band needs to set up. And that the music will be delayed until the area is clear. Leaving it up to them to relocate things or make the music late, at their option. Sometimes they get people to move, sometimes they wait until the folks leave and scramble to move the tables. At that point I can start, and will make every obvious effort to get set up quickly but making it clear that it was management's choice to delay the 2nd half of the evening because of the 1st half. Which part makes them more money is their bailiwick, mine is just the entertainment part they hired.