Confusion is created all too frequently when businesses post incorrect signage. As examples, in Flower Mound alone, I have seen a 51% sign posted at a convenience store on 2499 as well as the semi-new Fuzzy's west of Marcus High School. This may simply be the result of the business receiving a packet of signage from TABC when they receive their liquor license and some uninformed employee putting up the wrong one - or putting up both, not knowing any better!
In any event, if you see a 51% sign posted in a questionable location, do not hesitate to "drop a dime" on them at 940-349-2877 (or http://www.tabc.state.tx.us/contact_us/counties/Collin.asp). TABC will generally send out an agent to investigate and the proper sign will likely be in place shortly. ;-)
What we don't want to mention to the business or to TABC is the 30.06 sign, which may be a topic for next time.