or their traffic is so low it keeps the error rates down.
Happy to stand corrected, but I thought DSL error monitoring continued just as effectively on a quiescent line as a busy one? Agreed though, some folks do probably switch off modems overnight.
Per monitoring lightning strike data, I would imagine the data providers expect handsome payment when the data was to be used for commercial gain. That would be one disincentive against its use.
Per DLM wide area events in general, the first place I ever saw it mentioned was in a BT patent. If BT hold the patent, it might explain why nobody else can do it, or at least not without paying BT for license.
Ps, edited to remove accidental irrelevant smiley. Darned, fiddly, mobile phone keyboard.