That's great, and a mix of all kinds of signs is to great effect. (People from all sorts of demographics using whatever means they can to be heard.)

Sometimes the sign-makers are artistically inclined, and may have access to better materials.

The most memorable example was at the political demonstrations (and counter-demonstrations) leading up to the Massachusetts constitutional convention that legalized gay marriage. For the State House one I photographed (learning photojournalism on the side), the anti-gay-marriage people were mostly bused in, including a pair of angry-looking old nuns in black full habit, and handed out the same ugly stock sign. (There's an obvious joke that they couldn't find a graphic designer who was sympathetic to the anti-gay cause.) Separated from them, across a street was a huge counter-protest, with an ocean of all sorts of creative, colorful, and positive handmaid signs, held by generally good-natured and thoughtful looking people.