We have yet to make a final decision, but are discussing sending the opt-in form to EVERY consumer.
Reasons why:
1) opt-in is at the account level, so this allows us to send one per customer instead of one per account without the need to target only debit/ATM card consumers. This may overall save on postage/marketing (maybe, maybe not, depending on how your FI breaks down on card holders).
2) it gives us a chance to market a new service to non-card holders. My guess is that this is the primary reason we're leaning toward this option... revenue replacement!
3) if said customer later decides to get a debit/ATM card, we MAY already have their opt-in preference.