[RFEngineer]

You may be right......

The two things I have heard regarding manufacturers implementing winglets were:

1. You effectively increase wingspan, lowering vortex drag without actually needing to modify ramp accomodations

2. Look cool

I'm not a pointy-headed aero type, but I know there are a few around here who may be able to speak to the technical issues more succinctly.

[Gunrunner2]

I'm not an engineer and I didn't spend a night in a Holiday Inn Express, but I think the winglets are to reduce wingtip vortex drag.