How exactly do you expect those executing the warrant to tell if the gold really belongs to someone else or not? After all, wouldn't it be in the best interest of those at Liberty to lie and say that it is someone else's gold to avoid it being confiscated?
The only practical way for them to do it is confiscate it all and then figure out what doesn't belong to Liberty and isn't relevant to the case after the fact. Unless the warrant is extremely narrow, that is pretty much how they have to execute warrants to make sure they get all the evidence.
It can place a large burden on innocent parties, but unfortunately that is unavoidable a lot of the time, and they don't really know what isn't relevant to the case until they have gone through the evidence.