processing mail-based donations/subs with TMS

Greetings P+T crew!  The Guthrie Theater is anxious to move from Worldpay to TMS, but our Devo and Box Office teams are very concerned about the requirement to enter a CVV along with the credit card number when processing a transaction.  We still receive very large numbers of season subscription requests/donations via postal mail and understand we can't legally request the CVV along with the other cc info on these forms.  (I gather that legally our hand may be forced on the CVV requirement, with or without TMS, but we'd like more time to plan for this eventuality.)  How are other orgs handling this situation?