Thanks to all for your thoughtful replies and suggestions. Looks like the poll was pretty evenly split, just as here at home, between the 2 camps of:
1) DW....leave it alone; water under the bridge; no harm done; and
2) OP.....need to improve the world for future generations.
In the end , because of the remaining small tasks yet to be done, I opted not to risk poisoning the atmosphere and said nothing. I know it can be done by those who possess the relevant skills but, since I am not especially blessed with them and because the reaction is also dependent on the mood of the receiver (which I cannot control) , I thought the best tactical action was to do nothing.
My natural instinct, however, nurtured by years of corporate culture, tells me that I am missing a chance to improve the world. At work, we were taught that most folks want to do a good job and that usually what prevents them from doing that is lack of knowledge or training. Since I actually was yelled at twice (by DD in her CO apt and DW at home; same type of blind mechanism) , I want to think that I am not the only ignorant person around. We also had managers who could not understand how the same mistake could be made more than once and insisted on having us write abnormality reports detailing root causes and short and long term fixes to permanently take care of these issues. Perhaps that will be a future action when any emotions will be long defused.
I actually thought of but dismissed any need to discuss the matter beforehand on the grounds that the drapes had been removed and the operating rod/control was 4 ft above the floor and (at least in my mind) nowhere close to interfering w/ the refinishing of the floor. Same bad decision as not mentioning that the dryer in the garage was gas. Found it
later moved (hopefully only slightly) so that they could plug in their heavy-duty floor sander, I imagine. When we had the kitchen remodeled, the workmen moved the dryer until the gas flex line constrained them. Considered putting a permanent sign on the dryer then but dismissed it.
I am reminded by a co-worker's philosophy that it is impossible to idiot-proof life because there are too many of us (idiots) around
I also had already put up a note telling the workers to close the sliding glass doors( where the drapes were) vert slowly and to be guided by the black line I had marked at the center of the track since a normal unknowing person would cause the end plates to be knocked off......we've already made us of the lifetime warranty once already. Plus another note telling them that a bookshelf was earthquake-bolted to the wall and not to attempt to move it..........so I already felt like I was micro-managing.
The workers were not physically here when I discovered and eventually fixed the problem. They did come later to finish up but we were there to observe until the original problem when we had gone on a trip.
The good news is that DW is happy to be rid of the old worn carpets
and when DW is happy, so am I. Thanks again to all for your input and wisdom .