[people in/at this temple/restaurant/store] but [things in...]

(1a) There are at least forty visitors in/at this temple.

(1b) There are only a few people eating in/at this restaurant right now.

(1c) People like to shop in/at this store.

(2a) There are five statue in this temple.

(2b) There are ten tables in this restaurant.

(2c) There are thirty computers for sale in this store.

My non-native English speaking friends said you can have "people in or at a temple/restaurant/store but you have to say "things in a temple/restaurant/store".

Are my friends right? Many thanks.