I take your point in that they could be a bit more forthcoming with the details of these trials before they actually initiate them.To be honest, I do think the current extended STM trials are rather underhand. It seems completely out of order to extend the STM to outside of the publisised hours without any kind of customer notification :/
I still don't have a problem with the limits tbh, either the current ones or even the proposed ones which are currently being trialled. I'm speaking from a personal perspective here on the 20Mb service, not sure what the limits are on the lower tiers. Restricting downloads to 3GB for five peaktime hours in the evening seems perfectly fair to me if it maintains QoS for average users. Quite why all the "moaners" suddenly need to download multiple gigabytes of data during these hours is beyond me when they have all day and/or night to do it. The upstream limits are set to 74% of what is technically possible to upload at full speed during the limited period and is thus clearly aimed at those who leave their bittorrent clients running 24/7 to get themselves an "uber" ratio

The new proposed limits being trialled are for the daytime but are set at 50% of the current evening ones, so 6GB between 10am and 3pm which is still more than reasonable imo. When you can download over 60GB while you sleep, why do you need to download so much stuff at other times when it's more likely to impact other users on the network!?
I think a large number of customers have completely lost sight of the contended nature of domestic broadband tbh.