Well, see how you will get varying answers. I never heard of "not favour[ing] any particular team."
GO CUBS!!!
Yes OTWO. In addition to nationalism, favouring a team was also considered a form of idolatry. That was taught from the platform a few decades ago - at least in this area. Of course, since JW beliefs are professed to be consistent and united everywhere across the globe, we that were given that info then thought, that was the common teaching everywhere.
They had also proclaimed 'True Christians' are not to get a tattoo or have their ears pierced as that is body mutilation and shows lack of appreciation and respect for God's gift of the body we are each given.
It seems those talks are no longer given as parents of born-in female children commonly have the child's ears pierced while the child is very young. There doesn't seem to be an issue made.
Viewing the FB pages of active JW teens, often reveal tattoos which I suspect, are kept hidden from elders in the congregations they attend. As OTWO implied, some things remain: 'Don't ask, Don't tell'.