Ok, Im just wondering if this would be possible:

Lets say, for example, you make a game, and you want it to be open source. (Yes I know, sounds crazy, just bear with me.) Now, you can upload the source files to byond, but people are not always truthful and will change all sorts of things *including the credits).

Is it possible to have a game partially-open-source and make it impossible to remove the credits? IE like having an encryption on a certain code file that makes it uneditable but nessesary to the whole project functioning? (IE2 Anti-leech)

Or would it be easier to make some sort of text parser where text files saved to the player`s pc that were editable, and use them to construct the maps/objects/mobs etc. and keep specific parts of the code constant?
Being somewhat familiar with Open Source, I'm gonna have to say no to partial open source. Really, the only thing you can do is release your code under an open source license and hope that people listen to it. You aren't going to have the resources to actually challenge somebody if they use your code without releasing theirs as open source or giving you credit.

That being said, there are tons of demos and coding examples all over byond, so I wouldn't be too worried about it if I were you. I know I plan on letting people view the source to anything fancy I do (whether it's the full game or just a few procs).