Back in 2007, I declined a charter job with a similar compensation structure (base salary plus daily pay) because 1. while the claimed total compensation was over $65k/year for a Beechjet SIC, the guarantee was sub-$30k in a busy east coast metro and 2. as a pilot, I have absolutely no control over how much the airplane or airplanes I'm assigned to fly. Good thing too, because a year after I turned it down charter demand (and bizav in general) fell off the proverbial cliff and I'd have been making MUCH less than I did as a regional airline FO.
While I understand the management perspective of trying to control payroll costs when slow and provide an incentive to work when busy, I also don't see the point in continuing to employ people who evade doing their jobs.
To me, its fairly simple - you are paid to fly, you are assigned a trip, go fly. There are plenty of folks looking for work today that would be more than happy to do what they are paid to do when a trip gets added.