It might be unlikely, but it is still my responsibility to ensure this
speed restriction, not atc's. Am I misinformed?

Regarding the 2500 foot rule, it's prefaced by something like "unless
authorized or required by ATC...". If ATC says to keep your speed up, I
would say that counts as an authorization to keep your speed up.

Jose
--
He who laughs, lasts.
for Email, make the obvious change in the address.