It is a laudatory suggestion, but unenforceable as "mandatory".
It is nice that the ability of others to add Keywords is available.
OTOH, I believe that there needs to be more discipline among those who overload their posts with topics and keywords. It defeats the purpose of having such capabilities. ("Breaking News" abuse is the classic example.")
While we're on the subject, I'd like to take the opportunity to once again humbly suggest refinement of the "Topics" selection that's available. In particular, I think more countries and geographic areas can be added to those already listed.