I made trials recently (about 2 or 3 weeks ago...) and it's IP based now.

On my laptop, I made 3 trial accounts, then was locked.

So I just connected to my friend's network next door using the same laptop (without rebooting or resetting anything on my computer or browser except for the wireless connection) and was able to make 3 more then was locked again.

For all the trial accounts, they each had a different contact info and address and different email addresses from one another.