Clowns, et al - whilst I appreciate your "concern" for the validity of the qualifying cross country flown by many students, I would point out that even if they did fly to "towered airports", they would NOT be allowed access to the tower to get a ATC'er to sign the relevant form.
This all stopped in the USA following 9/11. And, even before then, no American ATC'er would sign the form to state that the standard of airmanship or landing was good - they are too freaked out by the possibility of litigation should anything happen later.
Whilst working as the (supposed - at least, theoretical) Head of Training of a Florida flight school, I did argue the case with the CAA about this very subject.
The school - as all schools are - was obliged to write both an "Operations Manual" and a "Training Manual". Part of the Training Manual was the requirement to have the standard form signed by ATC at two 'remote' airfields. As this was impossible, I was not prepared to write this section of the manual and then completely ignore it (as all the other JAA schools do [to this day]).
I insisted (and the CAA inspector agreed) that the form be rewritten to say that somebody, ANYBODY, (even the guy mowing the grass), could sign to say that the aircraft appeared to arrive alone and at what time the person was asked to sign the form. Remember, the form suggested by AOPA is only a SUGGESTION!!
In this way we could check the "leg times" and fuel burn of the aircraft to see if the student got lost en-route - but that's all that we would know.
Before I got the opportunity to write this section into the manual other persons at the school got the idea that THEY should be the Head of Training and engineered my departure, so it never happened.
The chances of ANY USA based JAA student actually complying with the AOPA suggestion are slim to zero - and the CAA know this.
For once, it's not the schools fault. I'm not aware of one single student ever getting two signatures from ATC'ers - and I've been out here, doing or overseeing flight training, for almost seven years.
There is, however, no reason why the written examinations should be (set, or) marked by instructors, receptionists, accountants and/or flight school owners (or their mother).