I believe that is incorrect. If there is throttling involved, then the throttled speed is uncapped, and the "full speed" is limited to x number of GB (whatever the AUP states).
For example, let's say a service is advertised as:
4Mbps uncapped
but somewhere in the AUP fine print it says that the service is throttled to 64kbps once you exceed 60GB.
Then calling it 4Mbps uncapped is incorrect (and very misleading. Dishonest, in fact), because the user does not get uncapped access at 4Mbps, the user gets uncapped access at 64kbps, and 60GB @ 4Mbps.
The honest and clear presentation of this product would be:
60GB @ 4Mbps + uncapped 64kbps
There is no room for confusion when stated like that.
What the service providers are doing is taking the speed of the first part of the product (4Mbps) and claiming it applies to the GB limitation of the second part of the product (in this case, no limitation, i.e.: uncapped).
That is as incorrect as doing it vice versa (stating the product as 60GB @ 64kbps).
The next time someone lodges a complaint, that is what they should argue.