Can a musician missing their instrument at home visit music shops purely to play in-store, not to buy? [closed]

When I travel, and missing my cute piano from home, I like to search music shops having digital or acoustic pianos and go there, and ask to play one of them.

I didn't meet yet one seller saying no, don't play!, but I'm just wondering how okay is this practice?

In fact, I made friends by this method and I met friendly people in these shops, who even played with me (in one of them, we ended up with having a one hour long jam session–with guitars, drums and piano–and they closed the shop one half of hour later).

Usually, if I can buy something small from these shops, I do it (so, along with the videos, I have some physical memories).

What is the ethical part of this? What are the things I should be careful about? Is what I do good at all?

I did this in Europe and India, so far, however I'm looking for a generic answer.

I saw a similar question regarding the pianos housed in the lobbies of hotels. However, I guess my case is a bit different.