I suspect that Google can detect road construction using data mining techniques...it's the sort of phenomenon that is relevant to mapping only because of its effect on movement.
I apologize for not being more clear, but when I said road construction I didn't mean just fixing of roads but adding new roads. In order to have those new roads in your system you need to update your data set.
I have fallen victim to this. I bought a new used car (it's new to me but a 2007 model) that has built in navigation. Between the date of manufacture of the nav disk and current date, an interstate was added/modified near me. Now everytime I go by that area my GPS says I'm in the middle of a field. In reality, I can't see a customer filing a ticket with Apple to get that road in the GPS system. Even if they do, Apple would most likely need coordinates. This construction of new roads is what TomTom has a temporary strategic advantage over Apple (only temporary since Apple could get a department together to monitor all new roads).
Have you seen the iOS6 Maps problems-reporting UI? It's simple, it's fast, it's right in the place where you encountered the bug.
The other thing you ignore is that people want their local data to be correct in the maps they use, for practical reasons. I too reported new construction around my home everywhere I could, because it's, among other things, in my best interest to have my address easy to find (by guests or postal drivers, for example) on any GPS out there.
