That's how they do it. My neighborhood had all that work done last year, and almost every time the cones showed up when the work started, back-dated to several days prior.

Sometimes, though, the cones would come out with the no parking signs, nothing would happen, and then work would begin after the no parking expired.

It sucks, and they really should try to do better, but at the end of the day it's probably more important to get all of the lead lines replaced than anything else. It is obnoxious, though.

Also wait until you see the quality of their temporary patches! They'll make you forget all about their [lack of] signage and notice.