Not necessarily. You are assuming that the CM can verify the KTTW for every person just as fast as if they were looking just for the wrist band. If a mythical Disney ride can handle 20 guests per minute, but the CM can only check in 10 per minute, your will suddenly have a line. And yes, this line will indeed be longer than before. It doesn't matter than the ride queue and the ride system themselves won't be affected if you cannot get into the queue itself. Think about it. If there are 100 people ahead of you, during normal hours you would get onto the ride in about 5 minutes. But, if our friendly CM can only check 10 KTTW/minute, then you have a 10 minute wait. Yes, once you get into the queue you should have no wait as the ride will have been dispatching empty vehicles, but you still have a longer wait.
Quoting the WDWMagic estimates for capacity on Space Mountain, Capacity: 900-1200 per hour; 2057-2500 if both sides open. Using the low end number for 1 track of 900 guests, it means that a single CM needs to check 15 KTTW per minute, or one every 4 seconds. I have been at EMH where the ride was full, and also others where there was practically no line. So this could be an issue.
Assuming the reports from CM's that they use 15-20 CM's to pass out wristbands, splitting those 15 CM's throughout the 14 attractions currently listed as being open during evening EMH's at MK would only give 1 CM per attraction to check KTTW, possibly forcing the 4 sec per guest check.
Now yes, if the ride isn't full, or the rides with less capacity it's not nearly as much of an issue - I.E. Dumbo should have more than enough time to check the KTTW for the next load cycle, but the people eaters definitely have the possibility to create bottlenecks at the ID check station.
I wish people were smarter than we can give them credit for. But just look at the CS lines. How many times have you been stuck behind a guest at the register who still hasn't decided what they want? One would assume that after the first few times they would figure out they need to decide first, but that is apparently not the case.