Trying to calculate the probability of having a meet-cute in the gluten-free aisle of Tesco.
Tesco, on average, has a wider variety gluten-free products in a single aisle than most other stores.
Which means people are more likely to spend time in that aisle deciding on what to purchase.
There is a theoretical possibility of a meet-cute anywhere, but I would suggest that common interests (like the mystery shelf at a bookshop or the gluten-free aisle in a Tesco) have a higher probability.
Frequency definitely matters, but is every trip equal? In a bookstore, you are usually looking for something new, but in a supermarket, you may simply be purchasing the same products.
Is a better question to create a matrix of the places with the highest theoretical probabilities for meet-cutes?