Your question is problematic because it doesn't say how this information will be helpful to you in answering a research question for your genealogy and family history. From What types of questions should I avoid asking?:
You should only ask practical, answerable questions based on actual
problems that you face. Chatty, open-ended questions diminish the
usefulness of our site and push other questions off the front page.
As the question is written, you are asking the community to evaluate the information that was given to you in a book which you've read, but you didn't cite. We have no information whatsoever about this alleged Beauchamp family, so any reason we might give would be pure speculation. Social rules, like laws, differ depending on time and place. Without a time frame or a location, it isn't of any use in putting historical records in context, or helping you solve a problem.
You're also asking us to speculate on the actions that your own family might have taken:
I come from the Garcia family. Would any of my parents or grandparents
say, I was a Garcia every time I did something they didn't approve of?
If you don't know whether or not your own parents criticized you or any of your siblings by saying "Garcias don't do that" then how are a bunch of strangers on the Internet supposed to know?
This might be an entertaining discussion topic on a forum, but open-ended discussions aren't on-topic for this site.
From What types of questions should I avoid asking?:
If your motivation for asking the question is “I would like to participate in a discussion about ______”, then you should not be asking here.
Also, an open-ended discussion that covers any time and place -- surname-based 'enforcement' around the world and through the ages -- also falls afoul of this guideline:
Your questions should be reasonably scoped. If you can imagine an entire book that answers your question, you’re asking too much.
In conclusion, if there are so many issues with a question that the community has multiple answers for why the question is not a good fit for our site, that's a strong indicator that it doesn't belong here.