Thanks for the question.
I live in the United States, so I have no knowledge of what is said or talked about in the link you provided. I do know that in Europe the laws require that electronic devices have an auto power off function (they are trying to save the planet - which, I guess, should be commended). Technically speaking, what we incorrectly call an On/Off Switch here in America is actually a Standby button, because as long as the instrument is plugged in, it is drawing a small amount of current from the wall.
In America, we still turn on the air conditioners during Summer and open the doors! :-) I'm not recommending this, but that is basically how we roll over here. There are also regulations in Europe about batteries touching each other when used inside products, that do not apply everywhere. In an effort to not have to build separate models for every part of the world, companies, like Yamaha, have to attempt to comply whenever/wherever possible (lest prices have to go up). Imagine having to build different models for every country, yikes!
The Yamaha CP300 was unavailable for a brief time here in the USA and reappeared after being retrofit with the ability to auto power off. We have been telling folks for more than a couple of years now, that products in the future will all have this ECO-mode... Which is probably the right thing to do overall. It has been my observation that musicians are (like average people) AFRAID of change. They are scared that the instrument will power off in the middle of playing. (It will not).
Well, that is as silly as thinking if you sailed West from Europe in 1492 you would eventually fall off the planet. :-)
Yes, the fear of your instrument powering off in the middle of you doing something is JUST AS SILLY!!!!
The MOX was updated at version 1.01 to add this feature back in 2012. The MOXF (2013) features this function from day one. Here's how it works in those products... If you leave the unit ON and do not touch it or make any changes, the instrument will power itself Off after the time YOU set for this to happen. It is a UTILITY mode parameter. But if you have EDITED anything (small "e" appears in the upper right corner - signifying that you have Edited a parameter but not yet STORED that change) the auto power off feature is automatically defeated... And the MOXF will not power down.
So you will never lose any edited data, since the instrument will not power down while the Edit Buffer is occupied with information you have edited.
If you choose to opt out of using the ECO-mode you can STORE this preference in your UTILITY mode settings. You do so by setting AUTO POWER OFF = OFF (All recent Yamaha keyboards you can also defeat it by holding the lowest key while powering On... Then you can store this setting.
While in [UTILITY] mode
Press [STORE]
This will write this preference to your instrument's internal Flash ROM. And this setting will remain there until you either change it or you execute a FACTORY SET.
Your question is really unclear to me... Are you questioning the honesty of this European poster? Are you worried that this function is hidden somewhere within your Motif XF? Are you worried about this feature, in general?
I personally have not seen this yet in the Motif XF here in the USA, but fully anticipate that ECO-mode is a reality now, and that we all will need to embrace it going forward. Given that the CP300 was recently redesigned to accommodate this feature, I'm not going to be surprised to see it implemented eventually in all products.
There is no downside to it. The world is not flat. You will not fall off the planet. You will not lose any of your XF data!