Yes, because that's the thing that makes it open and able to survive the death or corruption of the entity holding the copyright.

If nobody can sell me the printer or replacement parts for it after the initial vendor inevitably goes out of business, that's a problem.

As much as this is nice protect, and physical one so different things any, still you cannot give/sell some software/design/media and restrict who, where and how someone can use it (noncommercial, not in this country, not at that phase of moon) while calling it open source, public domain, or similar.

As long as softwsre isn't going to be proprietary, it is a good idea just shouldn't misguide about being open source.