There seems to be a new field added to the virtuemart 3 checkout page. Its label is COM_VIRTUEMART_CNOTES_CART.
Should we be able to use a different label on this within the theme?

Thank you.

Hi,

Customer Notes is a "shopper fields", can be disabled/enabled/edited through Virtuemart Backend >> Configuration >> Shopper Fields

I don't understand what exactly you meant, but if you are asking how to translate/change it;
Open the language INI file;

/components/com_virtuemart/language/en-GB/en-GB.com_virtuemart.ini

add this line to the bottom;
Regards.