How can you make 17 year-old customers switch to a bank account for grown-ups?

Present the account as the 'adult' bank account, using the international symbol for explicit material (18+). The mailing describes some of the joys of being over 18, and points out that all of these joys cost a lot of money. Introducing Rabobank's adult bank account – the account for 18 year-olds and older.

Usually only 6% of the 17-year-olds respond to mailings for this bank account. To this mailing, 24.6% responded.