Back around 2004-2007 I had two jobs, one was salary and one was hourly. The salary position was a customer facing one where when the customers weren't there, often there really wasn't much to do. The hourly job was consulting for a financial institution providing tier 3 ops support for their data systems (handling problems with things like Bloomberg Data License, Barra, MSCI, etc.). Both employers knew my time was being split but didn't care.