I have zero interest in reporting bugs that may or may not be already known, it's just too much hassle.
I had enough university projects where it was a quite hard fight to convince users (from academia) to use a bug tracker. Now do that with arbitrary users. Please go here, create an account, register your mail, select the subsystem, type the bug description here...
Be realistic: Forget it. Even in my unversity projects, most users wrote emails, much to my dislike, because it was just easier. Users know how to use a forum. We collect bugs, decide whether that even is a bug in first place. Keep the barrier low for users. A forum is ideal for them - easy access, known medium, low barrier. We filter, collect and feed the bugtracker.
At least you could have a text file somewhere, listing a summary of all known bugs. How hard can it be to generate such a list from your internal bug tracker
Not hard. But why would that help? Would users read them before reporting? No. Reading bug lists requires understanding bugs, requires some technical background, and investing time for it. Thanks, but no, thanks.