Air carrier ground personnel reported noticing passengers with a rideable carry-on bag that is prohibited by the airline's policy. Ultimately; the passengers were deplaned and the bag was removed.

Narrative

Passengers on the ZZZ1 flight had a rideable carry-on bag. The first thing I did was call up to Security and I spoke to Person A to let him know the situation. I asked him if I should file a report and he said there's no need and that he'll notify ZZZ Management himself directly. My Supervisor happened to already be at the gate and was present while that family was boarding. She noticed the bag looked different and asked me to take a look and immediately I knew that was prohibited on Company flights. My Supervisor was unsure but luckily Management sent out an email recently in regards to these type of bags and Company's policy. I was surprised my Supervisor wasn't aware of this and also was unsure of what the protocol is. The passengers ended up being deplaned and removed from the flight so that they can sort out how they will be able to still keep their bag without flying with it. I did explain to them Company's policy. I ended up rebooking the family of 3 for the next day. Per my Supervisor's request; she wanted to provide a hotel accommodation and meal vouchers. I did what she asked and sent it to the passengers. Another thing; is they flew from ZZZ on this same date and ZZZ must have not noticed this prohibited bag and allowed to connect with them to ZZZ2. Luckily I was there to intervene; and to ensure everyone's safety.