Every now and then, the CM at the entrance will hand a red card to a guest and ask them to give it to the CM at the front; this is at least part of how they estimate the lines - it may only be one input or used as a correction factor or confirming factor. So, yes, the wait times can end up being longer by the time they get the card especially for popular lines or ones with long wait times. The Lines app does something similar, although I find it much more accurate. Subscribers can upload the posted wait time and then set a timer when they enter the attraction. When they get to the front, you turn off the timer and submit the results. They then use a mix of the actual data, posted data and an algorithm honed over many years to estimate the actual waiting time. On Lines, you'll see what the posted time is and the estimated "actual" waiting time. It's interesting when you use Lines and set the timer. I've been in line some times with friends and when we get to the front they claim that the posted and/or Lines estimated time is way off (i.e., we waited much longer) but the timer shows that it was close to the estimated Lines app time and was much less than what they felt it was.