For those of you who do not believe in the X day schedule check, I guess technically a pilot could wait till 0001 of the on call day to check the schedule, thus not checking the schedule on the X day.

...but the PWA clearly puts the responsibility on the pilot for checking and acknowledging an assignment for the first on call day. How else do you you interpret section 23.S.3.d.2.b) and the associated note?

23.S.3.
d. will be notified of his assignment to open time under Section 23 N. or O. by one of the following two methods:
1) telephone contact from Crew Scheduling.
2) electronic placement of a rotation or conversion to short call that is placed on his schedule prior to:
a) his release from a rotation, or
b) nine hours before the end of his last non-fly day (other than a vacation day) before an on-call day.
Note: A pilot is responsible for ascertaining whether he has been assigned a rotation or converted to short call under Section 23 S. 3. d. 2) b). Crew Scheduling is not required to make telephone contact for such an assignment or conversion.

or 2

3.S.2.a.5) Note Two: Note two: A pilot is responsible for ascertaining whether he has been so assigned a rotation. Crew Scheduling is not required to make telephone contact for such an assignment.