Admittedly I not sure if this is so much of a IC2 bug as it is mod-to-mod related but in the name of compatibility I submit it here. The personal safe is meant to be completely unmodifiable by any player aside from the owner however with the use of any mod that adds block breaking/harvesting blocks such as either minefactory or redpower you can easily destroy the chest and collect its contents.
[Bug?][1.23]Easy personal chest breaking
-
-
- Official Post
Not much we can do about it. The Block is even marked as unbrakeable in the code, if mods prefer ignoring this fact, there's nothing we can do about it.