By no means do I suggest that the Taj treated you properly in not allowing you access.
They could have explained to you how to avoid this.
Most day visitors that come to the Taj park in the self park garage as it seems you did.
Not many choose to drag their luggage through the entire length of the garage and the casino and then down the escalator to the front desk.

Might I suggest that in future visits to any of the casinos you pull up to the port cochere where you can unload both your luggage and your family within sight of the check in desk.

Once you check in, you are given both a room key and a guest card. You can request as many guest cards as there are in your party. Your name, room number and date of departure are on the card that would identify you to anyone that might ask.

As far as your suggestion regarding the kiosks, believe me I agree 100%.
The trick there is to know the layout of the casino and know where the kiosks are that are not used as frequently.