Not only do I RIP....I prewash it! that helps bring it back into alignment as well...and if it is off grain, it will really show after it is washed..
I iron it after I rip...so that the edges are not rough.
as a side note..it gets off grain when it is printed....that is why sometimes you can not get it on grain/straight no matter what you do...
I find that if I RIP the strips for sashings/borders, and then trim them to size, they will generally lie flatter and be truer to size!