If you are only there to pay for the item your daughter has stood in line for then it shouldnt be a problem. If, however, she got the laptop, but then you decided to grab a doorbuster tv when you got there as well, there may be some others behind you in line with a problem. Over the course of her waiting in line with these people, though, there will be plenty of opportunity for small talk and mentioning to those around her that you will be coming only to pay for her item and that's it. I'm sure if she does that, I'm sure everyone around her will be understanding. Best of luck! :)