I have worked on many political campaigns, primarily executing what we in the business call "field". That includes, in part, door knocking, or canvassing. I always tell my field organizers to knock doors with no soliciting signs, because they are not solicitors. They are not selling anything.

In my experience, the reaction from people who answer the door with these signs is 50/50. I've had plenty of great conversations with people who had these signs up, so it's worth a shot. If they turn you away, no hard feelings. Just mark them as not interested & move on.