sieve/managesieve/time and ACL

Hi,

suppose I upload a script to the server using managesieve. A perfectly 
fine script which contain only a fileinto command for the mailbox 
/mumble/stumble. The next day, someone who doesn't like me changes the 
ACL on /mumble/stumble such that I no longer have the right to insert 
messages into it.
What should happen when a message arrives and the script wants to 
fileinto? I can't find any mention at all of access control in 3028bis, 
far less of access control which changes after the sieve is blessed by 
managesieve.
Arnt