I have a problem I can't work out how to resolve..

I have a "booking" content type with a reference field to the "customer" content type.. I want to create an "Account Suspended" checkbox field on the customer content type so that if a "customer" tries to save a "booking" and their account is "suspended" it will not save the new "booking".. And possibly show an error message telling them their account is suspended..

I have looked at all the rules options but the new node always saves even if you try and redirect the user "before saving content".. 

I have also looked at the rules_forms module which doesn't appear to be able to access the fields in the referenced entity..

So I am a little stuck..

Anyone have any suggestions how to do this?

Thanks..