Sasha, I appreciate the need for a new user to see the message, at least for a few times. Especially in those boundary conditions you describe. I agree with Robert above that I've never noted an appreciable difference in opening time. It's not like it takes twice as long to open the files I'm auditing. Then again, I've never used a machine at the low end of the hardware recommendations.
But experienced users will already understand the implications of selecting the option. It's also annoying when I'm editing 50-100 families that day to hit the button to dismiss the dialog yet one more time.
I hate to bring AutoCAD into the discussion, but one of the things that they do right is give expert users the options to turn off informational items that they know thoroughly and don't need to see again.