We do not accepted unsolicited submissions. You will see this declaration everywhere. It means don’t send us your script, it’ll be shredded and we’ll deny ever having seen it. No unsolicited submissions policies attempt to protect production companies and agencies from plagiarism claims.
But to breakdown the jargon further; technically even your query – specifically your logline – is a form of intellectual property. A mini version of your script. Sending it to a production co or agency without a request for it (a solicitation) is also an unsolicited submission. So technically query letters too should be trashed without being read.
But they’re not.
Enforcing the policy is at the discretion of the individual rep. Far from an impenetrable gate. Catch the right rep at the right time with the right pitch and even the most unapproachable shop can be (and has been) penetrated. So don’t let the declarations dissuade you. But don’t harass people either.