Well no, it isn't a reservation. It might be part of the name they chose to use to replace the old (more accurate) moniker of "priority seating" but that doesn't make it accurate. No table is reserved for your party. You simply get preferential treatment on the waiting list, and you might be seated right on time or you might check in at the podium to be told to come back later because they're running so far behind that they're out of pagers. I could accept a fee for true reservations where a no-show or unfilled slot due to a short-notice cancel means a table sits empty but that is not the case with Disney "reservations".
Yep, we've been told it is NOT a reservation (i.e., you are not guaranteed seating at say 7pm if your ADR was 7pm) and we are only put on the list. Sometimes, it works out nicely and we are seated within 10 minutes (but really, that's 10 minutes past our "reservation"), but more often, esp for dinner we have to wait 15-30 minutes and sometimes more. Once again, that is NOT a reservation but as PP said, a promise to seat you at some time. I can't recall a single time that a table was waiting for us EXCEPT when we had a party of 6 and made ressies at Le Cellier. As a party of 4 or a party of 10, we have always waited.
Now I have changed to try to get ADRs closer to opening, so we don't have to wait as long...but sometimes we just don't want to eat dinner at 4pm, ya know?
Regardless, if this were to happen and there was a screaming child in a restaurant I would hope that a parent would have enough common sense and courtesy to the other guests to take the child out of the restaurant until they calmed down.
Just hope you aren't seated next to me!

Seriously, if I am forced to keep a ressie or pay $40 then I'm taking my screaming or sick child with me and will make it known to everyone that the only reason we are staying is b/c of the new Disney dining policy. Perhaps a manager will understand and let us out of our ADR ... but perhaps not. However, this will be my response to a very bad and poorly planned policy.
Yes, I fully understand that my alternative is to just not make any ADRs but that is too much of a gamble for me since vacationing in Disney for our family means enjoying sit-down meals and not eating hamburgers/pizza each day

So instead I will gamble that we can make 2-3 ADRs in a week. We used to eat 4-6 TS in a week but I'm not willing to gamble that much.
Now do my children get overstimulated and/or sick regularly at Disney? No. That is why we enjoy doing table-service restaurants b/c our kids are normally well-behaved and like foods other than fast foods (only one time in 6 years did I take my child aside for a time-out at any restaurant, not just Disney, and she came back all calm). But I admit, I lose, as you say "common sense and courtesy" when Disney is not providing me with "common sense and courtesy" either.
As a parent, this new rule is just asking for trouble. I can only hope that Disney will change their mind as more 'nay-sayers', of which I am one voice their opinion directly and indirectly to Disney.
Has anyone gotten a response to their letters or phone calls to Disney asking why the policy was made? I know a lot of people were going to voice their opinion about not liking it, but do we know yet why it was made?
The response I got was same as PP wrote. Basically they say they are doing this to free up table space for others. But they can still free up table space for others w/o charging (my opinion, obviously) for those who cancel.