[salamandersauce]

I bought the Chinese food so why can't I put chocolate sauce on the rice if I want? Because the owner of the restaurant says no?

[DowsingSpoon]

What an excellent analogy! You can’t put chocolate sauce on the rice you bought because outside food and drink are always prohibited. You’ll be politely, but firmly, asked to leave. So, in a word, yes, because the owner of the restaurant says no.