There are a lot of drive-by commentless date changes. Much (but not all of them) are vandalism. They are often difficult to fact check, and these days with so much vandalism reverted by bots, I'm worried that even more date changes are being missed.
I believe this is one of the most serious and shameful areas of factual error on Wikipedia, although perhaps it is not the most urgent nor the easiest to improve on...
An example: Tonight I reverted a date vandalism to [[Pioneer plaque]] which was made over a year ago (http://en.wikipedia.org/w/index.php?title=Pioneer_plaque&diff=14242706&a...).
In that case, it would appear that the edits of a good user hid the bad diff.
Does anyone have any good ideas kicking around in their heads on how to improve this situation... I've thought of some things but I'd like to collect some ideas.