I think this depends a lot on your general schedule. If you are only training 8-10 hours per week, I'd squeeze the workout in a day early. If you are training 15 hours per week, skip it and have an extra rest day. Once you try to do it a day early a couple times you will learn how you handle it and can make a better decision.

I'm with MDCatV on the disruptions being the rule rather than the exception. I just had a lunch meeting come up a few minutes ago that killed my plans for a sprint workout today.