Do we want to flag this as an issue whenever we find a JUnit4 annotation? As in, if a developer simply still uses JUnit4 and hasn't upgraded to 5 (yet), do we flag the annotations 'because you shouldn't be using 4 anymore' or do we want to permit the usage of 4 as long as no 5 has been introduced yet?
The idea here is that as soon a project wants to migrate from JUnit4 to JUnit5, they will enable this rule (it is not enabled by default). The rule will then flag with an issue (severity bein "info") any use of JUnit4 annotations, to have it changed.
So, to me there is no need to think about the automatic enabling process, deciding to use the rule or not is on the user's side.