I don't have a URC, but in remotes that lack state tracking, I just add all the discrete off's for unused devices to the beginning of all my macros. I thought URC had variables and flags, so you could do your own state tracking anyway. Is that not correct?
In your case, the TV macro would turn on the TV and possibly the cable box and AVR, as well as turn off everything else (DVD, game console, etc.). The DVD macro would send discrete on's to the TV and DVD and possibly AVR, and send discrete off's to everything else (cable box, etc.).
If you don't want to do it that way, you could simply call your TVOFF macro at the beginning of every macro to save steps for your wife without having to do much re-programming.
If you have devices that lack discrete on/off, you simply use a boolean flag to keep track of the state. ON would check the flag, and if the flag is false, send power toggle, then set the flag, else do nothing. OFF would check the flag, and if the flag is true, send power toggle, then clear the flag, else do nothing.