Why allow cell phones for guests inside your house, when you don't know who is your guest?

1. This is a good question in many companies are taking mobile phones from their owners when entering the company, especially mobile ones, so as not to get cases of espionage or things like this

prevent industrial espionage via photos or recording

Mobile phones must be withdrawn at the time of entry to focus on work

Thanks to invite.

In this regard company rules are always preffered, no individuals are permitted to violate the policy except competent authority.

One of the ways is to put inside company a place where the guest could take a company phone and speaks, so that he can't take pictures or videos.