Yes it does, they can now arrest you for whatever the fuck they want, it will be up to you to prove your innocence in court. It doesn't mean they can search (although it makes it much easier for them to figure out a reason to search), but now with no legal barrier between you and them they can arrest your ass and even though they couldn't arrest her before opening the door she can be arrested for disorderly conduct now. If cops come to your door without a warrant then dont open the fucking door talk to them through it and end the conversation quickly and most important never give them consent or imply consent in any way to do anything.

Open the door and boom he can see other people and say they look underage, now he a reason to enter with no barrier to entry and can ID people. He can see a fucking baggy and that's reason to search, with the door closed he cant do shit at worst leave a fine/citation for noise violation.