This isn’t completely on point but I’ll share anyway.
When I had my pizza joint, it was just the rental of an existing tiny kitchen in an existing bar. One night they had a private party, rented the bar out, ran a tab, whole nine yards. These were people who used to live in St. Louis and were in town for a meeting, as well as some locals. They wanted pizza, so they ordered some of mine. They also politely asked the bartender if they could order in from a local chain. They explained that they were visiting, missed x-brand pizza, and St. Louis style pizza truly is a different animal than “normal” pizza. I didn’t make, attempt to make, or even desire to try to make St. Louis style pizza. I told them to “go for it”. I appreciated them asking, understood completely what they were asking and why, and was glad to let them have a good time. They kept ordering from me as well. They knew they were asking for something quite “odd” and respected me enough to ask politely and at least split the business with me. Obviously, this isn’t the same as having your own free-standing store and someone coming in and having the competition deliver, but the folks who were local saw what was going on and some even apologized. I explained that I understood completely and since I wasn’t offering exactly what they wanted, they were welcome to bring in what they needed to make their party what they wanted it to be.
As far as the thought of them getting food poisoning and not knowing what caused it… people eat different foods normally at least three times a day. It’s no different than trying to figure out if lunch or dinner was the bad food.
Put things into a difffent view if you will… there are 8 people looking to have lunch somewhere. 7 want pizza, pasta, subs, etc, but number 8 just really wants Taco Bell. So, do I gladly sell food to 7 people or lose all 8?
I’m not sure what loitering is, but I’m pretty sure it’s what we called “hanging out” 20 years ago. How would you have reacted if you couldn’t hang out somewhere that wasn’t busy, you weren’t bothering anyone, etc? Sure, they should at least buy a soft drink while they’re taking up your space, but unless they’re taking up a table you need or are being obnoxious, where’s the problem? Heck, I used to have to wait for my mom to pick me up from jr. high football practice. I’d walk to the restaurant next to the school, order a coke and drink it until she came. It wasn’t much revenue for them, but the place wasn’t busy anyway. Had they kicked me out, I’d probably not ever returned there to eat. The kid you kick out may be the child of that daily lunch regular you’ve had for 5 years.