Ever been a vegetarian in a beach town? I have. You walk up and down the boardwalk, breathing in the salty sea air, building up an appetite, and then discover that every single restaurant offers only surf and turf after two hours of searching for sustenance.
Pro-Tip: Spontaneity is nice, but so is a backup plan. Search for nearby veggie friendly restaurants on OpenTable before the hunger hits and the reservations are booked.