If you're using Chrome or Opera, try Youtube Options, and check out the "disable auto-play" options.
Yes, that is a good recommendation - I have that set on all browsers (that or "click to start player"). It avoids unnecessary utilisation/waste of bandwidth and other resources.
However, as I understand it, the thing about the above userscript (adds a Stop Video button) is that once you started
to view a video and then paused/stopped it, YouTube continued to feed it down into the browser's cache in the background, thus consuming bandwidth.
a facility for the user to be able to right-click the video and select the option to STOP
that background download, but now YouTube has removed
that option and forced it's own algorithm on you that makes the decision as to how much more it will continue to feed a background download to the cache before pausing the download and awaiting your further playing.
If a user wishes to maintain
control over the extent to which the PC system consumes limited resources (e.g., bandwidth, disk storage), then the above userscript (adds a Stop Video button) restores the rather useful control function that Google had removed.
There are probably many PC users - myself included - who would strongly resist the efforts of a third party (a commercial advertising company) that was attempting to wrest that control from the user.
There is a principle involved here in terms of the ownership of the PC's domain. Once you allow another entity access to and control over parts of that domain - an entity with interests that may be hegemonic and quite at odds with your
interests - then you may be unable to prevent that entity from taking over completely, leaving you forced into the role of a passive subject of the domain. Indeed, that may even be the objective. The Russian occupation of East Berlin and the Berlin Wall is probably a classic example of this.
This is arguably what Google's proprietary Chromebook could be attempting. In any event, Google have screwed about enough with my PC's domain already, with Google Desktop, and I for one have no intention of allowing them to encroach further into my life or my PC's domain. I have enough trouble keeping Microsoft away as it is.