The buying and selling of domains has enough potential hazards.
Why go looking for extra problems? The last thing you want ito do is to get into a legal battle with NFL, NBA, etc. Their pockets are alot deeper than yours. Unless your name is michael gates,
Buffett, etc.
And, you surely don't want to be the "test" case. That is also a no win situation.
I passed on buying 8 names today that expired. Eventhough, they were not direct conflicts. I don't want to go looking for trouble.
There are just as many opportunities to make money correctly instead infringing on a "obvious" TM.