A complete waste of time due to the extreme ease with which new email addresses can be created, as you point out. Criminalising the use of 'non-registered' email addresses should not be necessary, as any actual solicitation would be a crime already.
Implementing this is a waste of time and money on everyone's behalf.
This is another case of unjustified public hysteria leading to the police and government wanting to be seen to be doing something.
I'm 27 and I have 121 friends on Facebook. I've observed that people who are older than me tend to have less, and younger people tend to have more friends added than I do. 300+ seems common for people who are still at university.
It's like the average number of friends is inversely proportional to age.
Personally, I only add people that I actually know in real life, that I would say hello to if I met them on the street.