pparring said:
We just returned. Two adults and two children. We just shoved the 4 passes into the machine one at a time and went thru. The first day at MK there waws no fingerprint id. The next day at AK we did have to use the fingerprint ID. Only on the adult tickets. However, my daughter was in line when I shoved an adult ticket thru. She put her fingers in and the green light came on and on she went. Then my wife ended up with my ticket and she used her fingers to go thru. No problem.
The next day, MGM, only the adult tickets had to use fingers. Now remember my daughter was imprinted on my wifes and my wife was imprinted on mine.
We all used our own tickets for the first time and my wife and I had to use the fingerprint thing. It worked fine.
The next day at MK I realized that it just didn't matter. We switched tickets again and it worked fine again.
My conclusion. The fingerprint thing does not work at all. We were never asked for an ID. At least three of us were fingered on one ticket and the other had at least two. Worked every time.
It is my understanding that tickets bought in a group are tied together in Disney's system, so that any fingerscan from that group will work with any pass in that group. This is to prevent situations like the one above, where two adults accidentally swap their passes, or kids, or anyone in the group. But, sometimes the passes aren't tied together, it appears, from other posts in this thread.
To the OP: I'm not sure how this would play when the passes are purchased for different day lengths. It's possible (but I have no idea) that all four of your scans would be tied to the group of passes, so if you bought two 10-day passes for your bro and sis (and two four-day passes for you and your husband), that your fingerscans would be tied in with the 10-day pass fingerscans, and that it would all work out next time when you and your hubby go.
Or, because the passes are different lengths, they might not be tied together. The only way to test it would be to get the passes and try. If you can get through with your fingerscan on their 10-day pass, you're probably good to go.
One thing to think about, though, is that the finger scans occasionally don't work, even if you're using the right pass with your scan in it. You might then be asked for ID, which wouldn't match the coded name (or again, maybe it's all tied in a group, so I dunno).
Here's my gut feeling: If you come back next year with the six remaining days on the 10-day passes, and get flagged, explain (lying of course) that you accidentally switched passes with your bro and sis; that you and your husband were supposed to have the 10-day passes, not them. They'd probably check the system, confirm names, see that you and your H bought passes at the same time as your bro and sis, and fix it all. It's a plausible story, Disney really isn't losing any money, so you'd probably be able to clear it up at guest relations. But it's a risk you're taking to save roughly $90 on each ticket. You could lose it all.