In general, Debian has been rather strict with what licenses it allows in its repositories.
The right to transfer copyrighted works may also open people to legal action from employers in some countries outside the US. i.e. the identical contract text can have two different meanings depending where it is signed.
I prefer to license most works as Apache 2.0, and this ensures people can do whatever they need to get the use-case solved in whatever legal obligation they are encumbered within.
Note, implicit personal copyright is always in effect... The original author(s) must explicitly state the work is public-domain/CC0, or you could be in violation.
From what I've seen over the years, there are a few groups of trouble makers:
1. Companies from countries that have zero software copyright/patent laws. So will cycle GPL works into the closed-source production pipeline in commercial settings. i.e. the culture views the US concept of owning ideas as absurd.
2. Folks that think linking against a LGPL shared object for compatibility reasons obligates developers divulge source-code. Note, there is source code released under several different licenses for legal compatibility reasons. i.e. the work may be fine with static linking under one version, and at the same time violate LGPL with the identical binary.
3. submarine attacks... malicious/foolish folks that distribute works they have zero legal right to re-license, re-publish, or possess. For Unity developers on US soil, the store is peppered with works still owned by Studios that can get you sued out of existence.
CC0 and Apache 2.0 are the safest options in my opinion, but one still must trust the authors aren't poisoning the chain of trust with copyright violations.
This is another reason why out-of-band package managers are dangerous to commercial entities. Microsoft will be in business for a long time yet... =3