Croaking in your constructor is a bit harsh. How about undef? As chromatic said, if you dont' read documentation about something, like this, you get what you deserve. I don't agree with that, because if someone carelessly creates something great that ignores croak, and then you use that, you may find yourself with a bug 'cause of some odd situation.
But it also requires that it be checked for. I think returning undef has its place, but so does throwing an exception (a.k.a. - croaking). I see the logic in allowing the user of your object/class/module to choose to die or not, after all, this...
my $o = Class->new(@arg) || die "cannot create new Class";
is a common enough idiom. But I can also see the logic in throwing an exception and just requiring the user to catch that exception. For me, it really comes down to how you plan to structure the error handling in the rest of your code.
When I've done something wrong, I like informative error messages. Think of error checks like that as being kind of like strict.pm in effect. It saves me time in development. That someone who shoots themselves in the foot deliberately won't see the benefit is not a problem for me.