I don't know if it's common, but what you're talking about did happen. In 2007 someone slipped an ad into the Chengdu Evening News that said "Paying tribute to

I don't know if it's common, but what you're talking about did happen. In 2007 someone slipped an ad into the Chengdu Evening News that said "Paying tribute to the strong(-willed) mothers of June 4 victims". The clerk who took the ad didn't know about the 1989 protests, and so let it go through. The mainland Chinese I've brought it up to certainly knew about it though.