We go at Easter week each year and the exact week leading to and including Easter Day was blacked out (I remember because the blackout was our EXACT dates!

) All I remember is there were some sort of deals right around that week - because I tried to figure out a way to manipulate my dates so I could at least get some sort of deal on a few nights.
Not sure what your travel dates are so hopefully someone else can chime in as to if they got a deal in March or April since spring break nowadays covers a pretty wide span.