Do you refuse to eat in a restaurant that serves alcohol?

A Pastor near me takes the position of refusing to eat at any restaurant that serves alcohol of any kind. Doesn't matter if it's Cracker Barrel, Applebee's, Chili's, or a fancy sit down restaurant. If the place serves alcohol he refuses to even go in the door. He often speaks of this in his sermons.

His reasoning is that it would be a sin to support an establishment that serves alcohol. Using his logic, would it not then be a sin to buy groceries at Publix or Kroger because they too sell alcohol?

From a purely hypothetical perspective, would it not be more beneficial to have a restaurant full of people see you praying over your food than not? It seems to me to be a classic case of "straining at a gnat and swallowing a camel".

What are your thoughts?