Hi, it was suggested to me to do just that, so I bought a tube of silicone and had all intentions of doing just that when I happened on another post discussing the very subject.
The reason I have not is one of the posts stressed the importance of getting it perfectly sealed. If you allow one grain of sand in there, more will be follwing it's lead and over time it could build up and might mess up your coil performance and you might not know that's the problem.
My coil cover wont stay on to save it's life so it sounded pretty attractive to me, but for know I just put a few wraps of electrical tape on there to hold it on and remove and clean it after a hunt.
DR