It's not an issue of "can be done". It's simply a matter of usability.
According to Opera there were lots of users who didn't notice the difference.
I'm still fighting for them.
IMHO they were just not done right if it wasn't noticeable.
Going for sth. like this would surely work...
How can you not notice the big notice that pops up every time you open a private tab 😛
[
](http://photobucket.com/" target="_blank)
Not to mention the change of sites favicon...