Unnecessary risk? Im not saying there will be one because I really have no clue, but how do you know if it's unnecessary?
WindSeeker operates differently then Drop Tower, Drop Tower uses cables while WindSeeker does not. A totally different system. It is really nothing like Drop Tower except in looks.
If a teenager is trained properly then I don't know why it's really a concern (Maybe limit the age to 18? for liability issues?), and why does it matter that the Eiffel Tower is an observation deck?, IF WindSeeker did in fact have a control both at the top then it would work almost the same. An elevator would take you up, you would get out, and walk to your area.
At least, thats the only logical way for it to work.
Rwildman is right although he missed a key point. Let's say for sh*ts and giggles there will an operator positioned at the top of WindSeeker. When it comes down to it, what are they able to do other than stare at the ride as it goes around and around? It's not like a lift hill where they can stop the ride and yell at someone for having a camera out or for a guest doing something unsafe.