I think the reason we are seeing long wait lines is because literally anyone can use their device to get in line. Unlike Disney whose fast passes limit you 3 to start, and several that are booked up way before you actually Visit the park.
Since there is no real penalty or hinderance to scan your taptu, more people end up waiting in lines for rides they would have said..."I'm not waiting an hour for that!"
Well you can only reserve one ride at a time. So if you just scan your tapu all willy nilly, it's going to cancel the last reservation. If your set on riding the drop slide, and it's 100 min, you're going to wait 100 min before scanning your band again.