This was a very common thing media companies dealt with and still deal with. There are too many legal risks in even reading the idea. SOP is to send back the envelope sealed and with a canned response explaining that they don't accept pitches from the public.

I can't remember what the topic was, but I remember hearing a story about a company that was soliciting ideas from the public for maybe a joke book or maybe tv show plots. They got into a lot of legal hot water once they found out that the ideas weren't original and people were actually just taking them from other sources.

If anyone else knows what I am talking about, I'd like to know the name of the company.

they have to open the envelope to see what's inside - they get mail that is not ideas and they have to open it.

But I assume the people who get the mail are trained to see if the envelope contains ideas to stop reading and return the mail with the canned lawyer response.

How do they know what they are not reading if the envelope is still sealed?