What also might happen is:
Hornyguy signs up for a trial, jerked off so hard he passed out..Wakes up 3 days later and forgets about the site. After a month he checks his papers and noticed a payment by Ibill (for instance). Ibill??? WTF is an Ibill. Runs to his bank, says he never paid Ibill for anything and makes a fucking chargeback.
What have we learned? Always tell your cusomters by what name they will be billed