The FSM workloads used in concurrency suites generally run operations against the db object passed into each state function. That db object is constructed here from a session constructed here, ultimately using the sessionOptions object constructed in resmoke_runner.js here. That sessionOptions object is modified throughout the concurrency infrastructure based on the contents of TestData, but it never actually considered the contents of TestData.sessionOptions.

The net effect is that most operations done in concurrency workloads don't respect TestData.sessionOptions. This doesn't seem intentional, but I'm not sure.