https://musicbrainz.org/doc/Style/Release_Group#Secondary_types

The important part is:

Any secondary types should apply to most of the tracks on the releases within the release group. It's OK if some of the tracks do not fit the type (for example, if a live album has some bonus studio tracks), as long as the type applies to the releases overall.

The next paragraph declines to restate the important part:

As a general rule, always select every secondary type that applies. 

I think this needs to be modified to restate the important part (bolded is the change):

As a general rule, always select every secondary type that applies to most of the tracks on the releases within the release group.