Orrr just edit the string in the right text file to make it so the persuasion check they do when asking to leave never fails, imo this is way better than the "kill all deserters" option other mods/older versions of this mod have due to it being considerably quicker, and they will bug you *a lot*. Persuasion has a buttload of purposes besides telling to companions to stop being babies because they are all well fed, rich, and have insane relics that cost as much as small villages, so I don't feel bad about this tweak, plus, I just love having all the companions. It owns.
It's ok I won't tell you to read the faq or search through archaic threads.
Open up conversation.txt inside your Warband/Modules/POP folder
Find this string of text with search:
dlga_companion_quitting_persuasion:close_window
After you locate this string, look at my example below, this is what my current game uses:
dlga_companion_quitting_persuasion:close_window 4095 282 3 2136 3 1224979098644774912 -2 1 2170 3 1224979098644774913
The numbers you are looking for are the two red ones, I have the first at the initial default value the mod had it at, with the second number modified to make the check never fail, default is 12 or 13, and when you try to persuade them the game rolls from -2 to 12/13 and compares that roll to your persuasion, if your persuasion is equal or lower to the value that the game rolled, you win the check. I also read somewhere that there is a further debuff of -1 to your persuasion on every check, on top of whatever your roll was, not 100% on that though. Also remember, we could be running different versions and therefore may have slightly different strings of code, but some common sense is all that's required to find what is needed to modify. Remember, the default values of the two numbers should be -2 13 or -2 12, pretty easy to spot once you know those two numbers, no other numbers should even be negative in that general area.
and always remember, make back ups! It takes 2 seconds and saves you 2 hours(or 200, if you lose a save).