I don't pre-wash strips (though I do pre-wash everything else) - I just make sure to use a few color catchers in the wash and that I've got good quilting coverage and so far (knock on wood) that hasn't bitten me in the rear as far as shrinkage or bleeding goes. Although I received a "no-name" batik jelly roll as a gift recently and I don't trust this fabric one bit; this one I probably WILL pre-wash (by hand, in the sink), because I think it's going to be a bleeder. Or else just use it in a quilt with only black fabric around it!
The only jelly roll/strips I've used in the past (safely got by w/o prewashing) were Hoffman batiks, Moda jelly rolls, Kuaffman Kona rolls, and Connecting Threads strip sets. All of those I trust not to shrink or bleed excessively. The Hoffman batiks bleed a little bit, but so far I only see it on my color catchers, not on the quilt.