Any downside that exists to TRAC participation is it's hefty administration, staff training requirements, and of course that audit immunity extends only to the establishment, not the workers.  That said, the best part about TRAC is that you can enroll and benefit from its audit protection immediately with your tip declarations that exist today.  The IRS of course hopes that the TRAC efforts will influence and increase tip declarations, but those results are not mandated.  ATIP and TRDA participation, on the other hand, demand that specific targets are met starting day 1.