I would say that it's the parents responsibility to make sure that sports equipment is stored in the off season in a proper place. I keep all of ours in a storage tub marked by what sport it is and it's kept put up. When the time comes the tub comes down and all the previous equipment is there and I don't have to make hasty purchases.
Also, she and you knew practice was coming, she should have looked over the weekend and got all her stuff together so she could be ready on time. That's just planning ahead that, again to me, is the parents job. I feel that it's our job to teach the kids how to manage their belongings and their time and resources. If you had mentioned that she had practice on Monday, could she get her stuff together, then she would have had more than a few minutes to try and find them.
I would not make any of my grand-kids pay for their sports equipment unless the willingly destroyed it. Otherwise, it's my job to pay for it or say no, we can't afford it.