The way I see it is they probably have the same fear as all the other Assistants, the do not want the public to get hold of them and write malicious copies of it and such.
I have heard this argument before, but I'm not sure that I agree with it. The rationale is that if you release something as open source it an be recompiled with malicious code and redistributed.
First of all you don't really need the source code to do that, you could alter a library or the executable itself to steal passwords or do other malicious things.
Second, if that is a valid argument for not releasing something as open source, then it would apply to a whole array of software not just UO Assistants.
Someone could release malicious versions of Linux for example. Someone could prepackage a RunUO or ServUO with compiled executables that have malicious code. The list goes on and on.
Players downloading malicious software is an issue that is completely separate from UOSteam or Razor releasing their source code. If players are willing to download software from anywhere without making sure it comes from a trustworthy source, there is nothing you can do to protect them.
How does anyone really know there isn't malicious code in Razor, UO Steam, or another assist program? The answer is you don't really know. Without the source you trust but you don't know for sure.
The other argument is that it will show people how to hook packets, alter client behavior, and generally bot and cheat and make Life hard for shard owners.
This information is not only readily available everywhere on the internet, but it is also already available for UO.
MasterControl is completely open source and seeks to be a replacement for Razor's decrypt library.
UltimaLive is also completely open source and shows packet hooking, dll function forwarding, starting up a . Net assembly inside the client, and other things.
UOExt shows packet manipulation from a process outside the client.
UOSDK is a .Net library that has methods to manipulate all sorts of client files and do much of the grunt work associated with the client.
There are others too. Will releasing an assist program's source code cause more work for the community and individual shards? Maybe. The projects I just listed haven't so far. In any case, it's probably worth it.
How many times will the UO emulation community reinvent this wheel? We need a completely open source assistant and client launcher that the community can maintain when (not if) its developers move on.