[Koha] RFC: control character in a MARC record?

I've been helping someone debug a problem saving records from the reservoir to their catalogue and it seems that one of their sources has subtle errors in their data. The source record contains some control characters. One of the MARC:: modules reacts badly to that and crashes Koha. Is there ever a reason to include a non-printing control character in a MARC record and could/should Koha filter them all out? Thanks for any pointers, -- MJ Ray (slef), member of www.software.coop, a for-more-than-profit co-op. http://koha-community.org supporter, web and LMS developer, statistician. In My Opinion Only: see http://mjr.towers.org.uk/email.html Available for hire for Koha work http://www.software.coop/products/koha