If they have a fixed salary with a high objective to "make it" (e.g. if you sell less than $X, you get fired), lots of sales folks will skip on it because they can't go over, and most probably prefer to have a quarter or two or year at e.g. 70% salary while working on longer term deals, rather than losing their job for not being good enough within that arbitrary time period. And going over their quota can be wildly lucrative depending on the terms.
