Can't speak for creative fields, but it's remarkably common in tech. It was tolerable when wages meant we could afford rent or possibly a home and job security was excellent, but that's no longer the case, and thus folks are starting to push back on that excessive overreach.

See also "anti-moonlighting" and "anti-social media" clauses. Hell, I've seen the odd story of folks being fired/disciplined for their dating profiles before. If the government doesn't tell them no, companies will take every inch they can get.