Don't even bother telling them not to... they won't do it anyway. As mentioned, they only update if you complain of a problem that the software update addresses. Getting them to update it is almost like pulling teeth, as it requires a significant amount of time with the tech.
The SA will tell you everything they are going to do at the beginning of your appointment. I never say things like "don't update the software", etc. as it implies I know a bit too much. I DO say "don't wash it!"