No one ever gets close to the tubes....and my speakers have no removable covers.
The worst I've experienced is when a friend actually was paying attention when I remarked how loud my system can get.....he picked up the remote and cranked the volume. (My guns were unloaded and in their cases.)
Other than ear pain, no harm done. However, I won't play it around that "friend" again, and I dang sure won't boast about that aspect of my system anymore!