This crosses from quirky to unhinged:

During a phone order one season – 2018 I believe – a customer shared this story where he smuggled some Vidalias onto his vacation cruise ship, and during each meal, would instruct the server to ‘take this onion to the back, chop it up, and add it onto my salad ‘.

Eccentric at most. Unhinged would be chopping it yourself, at the table, with a Civil War cavalry sabre.