Actually it isn't what command objects are for. ;)
Grails Command Objects provide a simple mechanism to validate form fields that do not map directly to domain objects.
1) Actually there isn't any form fields on the page that will do the submit.
2) If there were fields, they all map directly to my Domain object.
Basically the Band object has its own form, which the original constraints are for.
There is a link on my left nav that is a "submit to app store" link (can be clicked at any time on any page), that will take the user to a purchase page.
when they click the submit to app store link, the method behind it will get the Band object from the Spring Security Context, since I am using the domain object as my User object for Spring Security, then it will call validate on the Band object, in which the new constraints need to be used to validate.
Does this make sense? There is no form with fields or a backing object needed.
Thanks
Mark