I think you could set it up anytime you wish. As long as you are not hooked up, you are fine! I personally have not set it up without hooking him up, but don't see why it would matter when, if you are not hooked up. Now to sit in a particular mode for any period of time with out movement may trigger an alarm, informing you that " hey, Ive been sitting here and havent done a thing". Lol Seriously, I see no reason not to, especially if you are strapped for time. Try it, and see what happens! It couldnt hurt!
God Bless,
lmunchkin