My experience is that, IF the filmmakers/producers have

1) A good script,
2) A history of completing previous projects at an acceptable technical level (quality lighting/sound/editing/etc.), and
3) A history of marketing these projects via festival screenings, DVD distribution, etc.,

THEN the filmmakers/producers will have little difficulty finding and/or convincing experienced actors to appear in their current project for little/no pay. ESPECIALLY if they're willing to cast these actors without auditioning them first.

For a short film that's shooting for one or two days over a weekend, I've always just provided copy/credit/meals to my actors. Very little commercial or industrial work occurs on the weekend, so most likely they won't be missing out on last minute gigs.

I'm still writing my first feature script, but I know that I plan to offer a daily rate (probably $100/day) to my actors, with zero profit participation. This will make things "cleaner" when the movie is ready for distribution.