Wow, Thank you, Thomas!!!
MKTO ought to put this front and center with their help article on creating a new custom MKTO fields and update their training for this, as well.
I was just about to create a custom field in MKTO for a survey where we ask for alternate shipping addresses for promo schwag...because there is already an "other address" standard field in SFDC Contacts, but not in Leads, we didn't want to include it in SFDC. But we figured if more than 10% of respondents were filling it out, we'd add it later and deal with the training for reps, then.
Thank you for saving us the loss of data!
You rock!
Lynn