Not that it’s really necessary/
worth it, but if you’re unsure about them using business checkin as your ‘guest’, also consider that you might actually be able to check in all bags together on your business booking, if you have sufficient allowance to cover it. In that case they wouldn’t need to go to the checkin counter at all.

Of course you’d need to take responsibility for their bags, which you may be fine to do as a family.