There was an interesting discussion recently on the security newsgroups regarding the misuse of strong names as security evidence for your security system (a.k.a security policy configuration).
If your strong name usage is other than code versioning and side-by-side execution issues or may be some CLI interop issues (ref. ECMA key), or perhaps as an excellent CRC check, you should read the following posts.
Valery Pryamikov has two interesting post about this topic.
First Part: Strong names are not security related thingies
Second Part: Strong names are not security related thingies (part II)