I'm Japanese and I live in US now. I can speak English a little.
Today I went to a cafe and I mistook taking someone's drink. (I already purchased, and it was same matcha). A staff realized that and she told me that I took wrong drink. And then she took it back from me.
When she gave it to the customer, I heard the staff said "someone steals yours". Maybe I couldn't catch exactly, but I heard the word "steal".
I know the correct sentence is someone *stole yours. But, I thought the staff was a non-native English speaker (maybe I'm wrong).
If the staff didn't say "steal", Do you have any possible sentence that instead of using steal?
In this case, is this expression suitable? Is that sarcasm? In Japanese, steal is 盗む. It's same meaning the word "rob". I felt she treated me like a robber. I think she could say it in a more polite way. If I were the staff, I would say "Another customer accidentally (mistook) taking your drink". (他のお客さんが、間違えてドリンクを取ってしまいました)
Some people might think you are a just more polite person. But, in Japan, If a staff say "someone steals yours" (誰かがあなたのを盗みました), I think it hurts a customer. (my side) Also rude.
If you are the staff, what will you say?
Maybe my sentence doesn't make sense (I'm beginner of learning English) but If you can understand what I want to ask, please give me comments.