I'm not so sure how realistic that really is. Many lines are difficult or impossible to back track to the same spot in, especially considering the line will have moved while you are gone. Some CMs *may* give you a FP to re-enter a line if you have been waiting a while and tell them on the way out that you have to leave to use a restroom, but you don't need a card for that, and it's really up to the individual CM on if they will do it or not.I think it might be useful for those who have been waiting patiently in a line, and just HAVE to step out. Show it to the CM, and they'll let you back in to where you were. Not positive on this, but I think that's what I read a while ago.
You're thinking of a DAS pass. It allows visitors with disabilities including autism, intellectual and developmental delays, etc to scan their bands at the CM kiosks at the front of each attraction. The CM then assigns a time to return to ride the attraction. This way, the visitor and their family can "wait" in a place that is easier for the visitor to tolerate. For example, we'll get a DAS for our kiddo for 7 Dwarves, go let her ride things with shorter lines or let her find a quiet place to spin around in circles to get her sensory needs fulfilled and then return to ride when our time (60 min or whatever) has passed. Hugely helpful for families like ours!I thought it was something to do with anxiety issues stopping people from being bale to wait in lines for rides?