i believe you're purchasing the right to use/own it
sure, if you own it you can do whatever you want with it, but that is at your own risk.
If the manufacturer has designed, copyrighted and patented the product then they own whats inside it and in most cases published for it.
Even though you don't see much legal actions going on in the world of copyright infringement in the material handling business that doesn't mean it wont come to pass.
It has been in my experience with other consumer products i have witnessed duplicating and altering(in alot of cases for monetary gain) where the mfg shut down websites, sued companies and even filed civil suits against consumers for the altering of devices or firmware within said devices.
Take the music/movie industry... everyone knows how they are going after anyone they can to stop the pirating of their materials. It wouldn't be any different in the material handling business. If they see they are loosing money because of anything interfering with their profits you can bet they wont sit there and watch it happen, at least not for long.
Take for instance all the manual swapping going on here....
if the right set of eyes ran across this i'm fairly sure they would come down on the site owners pretty hard and make them take heavier measures to try and stop it. If they were unsuccessful doing that they might even take higher measures and go after end users, it all depends on how adamant they were about putting a stop to it.
On the other side take a look at mfg's like Genie or JLG for instance, they post their information on their sites for anyone that wants it. It doesn't mean you have the right to change it in any way but its there free of charge.
With our business (the lift truck business) this same information is not available to the public and is guarded behind pass-worded/fire-walled servers.

I could go on and on about this but i think I've said enough.
now....
moving along to some other thread to help someone :o)