What you are suggesting does have some foundation in it, I know several grandparents monitoring their grandchildren & their care taker when the parents are out at work via IP Cameras. The catch here is that the child is not alone, but with a care taker.
Perhaps, I guess older kids e.g. Age 5 -10 could be engaged remotely by a care taker with common video calling, screen sharing tools; but only a child behavioural expert or those who have done it could answer it definitely.