Let me expand.
When me and my sister made use of the Single Rider system at IJA, there was a rather large group behind us. I seemed suspicious at first, but they had their SR passes. We waited in the projector room as usual, then were directed up the ramp.
Here is where the problem lies.
Anyone can simply slip an SR pass into their pocket at this point and insert themselves into the regular line. Lucky for us, we notified the CM at the elevator, but she had already seen that they snuck their passes away while coming up the ramp. They were directed up with us on the elevator, unhappy with their attempt.
This is a very small fix: simply navigate the SR's up the rest of the exit path to the elevator (there would be a new line for this), like California Screamin'. These two attractions basically have the same configuration in terms of the SR layout.
It's a small bug in a large pond of problems that are already hitting the resort, but it would be nice if someone addressed the problem.