Think about how this would look from the other side and the confusion it would create. Thousands of first time posts which don’t comply. Users asking why X can do something they can’t. Would those post need to be labeled as the “freebie”, adding to the noise?
Isn’t it more jarring to be told you can’t do something the second time around having just established that there’s no technical obstruction?
The whole principle here is that topics and replies to topics need to be meaningful. Short responses are absorbed by likes, reactions and votes. Notifications now are far improved because we can suppress pings from ephemera. Being notified by a topic because someone used their free post to +1 rather than throw a like on it totally undermines that.