Broadway ticket pricing is anything but consistent. We have up to five different price points in the theatre, discounts in the market place, Broadway Box and the TKTS line to name a few.
A recent study done for a Hotel chain showed that 75% of people researched said a "Best Rate Guarantee" would influence them to purchase.
So, by simply saying you guarantee the best rate, people find enough comfort to pull the trigger to purchase.
It may sound like traditional Broadway ad copy, but I don't see the downside to possibly trying this on shows where there really aren't any discounts on the market.
I believe people like the sense of security a "best price guarantee" portrays especially in the not so accessible world of Broadway.