@DavidCarlisle Oh, right. Yes, I see. No, I wasn't suggesting that at all. I don't think it would be desirable even if it were enforceable. I had more
tex.stackexchange.com/questions/213159/… in mind since it seems it would be more generally useful to have an MWE and a proper answer. (I'm not criticising anybody involved in this question. I just wondered about it from the point of view of usefulness to other users.)