Could I trust such a FlashPlayer update?
Unfortunately, if you're going to trust Adobe and their distribution of the Flash plugins, this is what you're going to get.  Many users are now removing Flash and trusting Google to keep the plugins current in Chrome, but this has the same level of security through obscurity.

If you're serious about these updates, you could close the window and go directly to Adobe to check your version and manually download updates: http://helpx.adobe.com/flash-player/kb/find-version-flash-player.html.

Best of luck!