The spec says:

"Array-valued or annotation-valued members of a qualifier type should be annotated @Nonbinding in a portable application.
If an array-valued or annotation-valued member of a qualifier type is not annotated @Nonbinding, non-portable behavior
results."

The case of arrays without this annotation should be managed to get a better portability. The equality of arrays is determined through "Arrays" helper (http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/annotation/Annotation.html) so i don't think there is any technical issue to consider arrays as a field.