Bear in mind also that when people are installing your module on whatever environment it may be, they really don’t know much about how your module does what it does.   They just want:   “It Just Works.™”   If your module is adversely affected by “something that is brought in,” then that will happen to the end-user also.   Whereas the tester might know what to do, and of course you know what to do and why it’s happening ... it might well be a complete (and incomprehensible) show-stopper for Gentle Reader.

The testers subject your module to all kinds of real-world environments including ones that you don’t personally have.   It is, to some extent, your call what to do in all of the use-cases they draw your attention to.