I'm not sure it's actually a security risk, but I cleared those items nonetheless. Thanks for the heads up!
I didn't think it was a security risk either, I just don't like anything being installed or downloaded of which I'm not aware.
There is similar in Firefox, which is why I have that also configured to ask me before downloading anything.
The Opera "Download and install Opera Unite applications etc.. without warning", means exactly what it says to me, and I'm not gonna give it the benefit of the doubt to mean anything else.
As I said in the first post, make your own minds up.
When you visit a website that's not in that list, and click on a Unite app download, Opera gives you a great big warning, and insists that you add that site to the exceptions list before it allows you to download the file from the previously un-trusted site.
When you visit one of the sites listed there (all on *.opera.com) it DOES NOT give the site the ability to install anything silently behind your back or any such nonsense - it simply means that when you click the install button, you get an actual install dialogue and not a big fat scary warning blocking the install dialogue.
For anyone familiar with Firefox, it has exactly the same system for its extensions - ever tried installing an extension from somewhere other than addons.mozilla.org?