USC doesn't prompt about major Terms of Use changes

From legal advice: When the Terms of Use for purchases change slightly, we can rely on its current statement that "We may occasionally change the terms of this agreement by posting an updated version, and all changes will go into effect at the time we post the updated agreement."

But when the terms change substantially, it would be better for USC to prompt you to accept them in the same way that it does before your first purchase.

I guess this would require USC and SCA, together, to decide whether the current version of the terms is substantially different from the version you agreed to. For example, USC could send, with each purchase, the version number of the terms you agreed to, or the date you agreed to them. Then SCA could return a flag for whether the terms need to be shown.

<https://wiki.ubuntu.com/SoftwareCenter#installing>: "If the item is published through MyApps or the ARB, and either (a) you have never yet accepted the terms of use or (b) the terms have changed substantially since you last accepted them, a “Terms of Use” dialog should open for you to accept or decline them."