We unravel this confusion by recognizing that there is no reason to add $2 to $27. By adding $2 to $27, the $2 is counted twice and the $3 returned to the guests is not counted at all.
What helps make this even more confusing is that it's only off by a single dollar. For some reason, a error of +/- one is more difficult to track down than a larger sum, perhaps because it's so close to the correct total.
This problem provides a means to understand how misdirection, and irrelevant facts and questions, can foil clear analysis. Additionally, the tools used to resolve this paradox are used in the analysis of a wide range of financial and scientific areas.
So, what ... the bellboy is lying sack of shit thief?