and think it's ok to distribute the /xt directory (or author-only tests)
I agree. Even if the tests are never run by someone else, they might still prove a valuable resource to another author. And if (somewhat unexpectedly cause my code is always perfect) bug reports start flooding in, it is always a good thing to have all existing tests for the distribution already deployed. It's much easier to ask a user to "just run this command(s) and post the output" than first having to haggle about how to send the test scripts and set up the test environment.
"I know what i'm doing! Look, what could possibly go wrong? All i have to pull this lever like so, and then press this button here like ArghhhhhaaAaAAAaaagraaaAAaa!!!"