Apartment block consierge and lost packages

I live in a large apartment block and all mail larger than a letter goes directly to the concierge building where it can be collected later.

There is no option to not use this concierge service. An Post and all couriers will deliver there by default, where it is signed for by the concierge officer on duty.

I've never had any problems, but I noticed recently that there is a new sign up at the concierge desk stating that they take no responsibility for lost or stolen packages. Presumably some packages have gone missing due to the large volume of them they need to process lately.

What's the legal situation here? Since they sign for each package, do they not take ultimate responsibility for it until it reaches the recipient?

If not, from a consumer point of view, is someone out of luck if their package does go missing since the delivery was actually signed for?