Split the Core option to disable GC to input and output, instead of both at once

In our RP guild we have a strict rule about no OOC in guildchat at all.
The option GCDisabled prevents the bot from outputting anything to it, but unfortunately also stops registering anything said there (and hence stops autoregistering new guildmembers for example).

Now I just hack in Sources/Bot.php the inc_gmsg function and comment out the return false line. (line #1454 in 0.6.5).

But of course I don't want to do this every update, so I was wondering if you could make one option to disable GC input and on to disable GC output?

Edit: After some more thought, it might be handy to have some modules do output to guildchat, so finer preferences on module level would be even better.