If you look at the sky (a very zetetic thing to do) you will notice a strong band of stars, popularly called 'the milky way'. This band traces a path across the sky roughly perpendicular (close enough to give the idea - there is a wobble that we will ignore here for simplicity) to the equator. This model shows the RET interpretation of the observed movement of the stars and constellations across the sky:
http://www.telusplanet.net/public/fenertyb/solsysGC.html
On A FET model, the milky way would inscribe an arm rotating around the North Pole (again, roughly. I've inscribed the path on the FET map, I hope no one minds):
Flat_earth-1 by
max_wedge, on Flickr
Since the bulk of stars in the night sky are in the milky way, and if it's true that stars exert a gravitational effect on Earth, then you should expect to see gravity readings change from minute to minute as the Milky Way revolves around the North Pole.
Now in case anyone hasn't noticed it, this model is not exact, otherwise we'd only see the milkyway at night for half the year. Taking into account the 23 degree tilt of the earth to the solar plane and the 60 degree tilt of the solar system to the galaxy, and the changing tilt of the seasons, in practice the South Pole is tilted more towards the galactic plane than the north pole, and most nights the galactic plane (milky way) is visible to most people on earth). However as I said this is a simplification. The gyrations of earth in the RET model fit perfectly with observations.
On the FET model, there has been no attempt to explain the odd path of the Milky Way through the night sky.
Nevertheless, through observation, we can see that it does inscribe a path regardless of which model, if either, explains it's machinations best. And if the stars exert gravitational affect we ought to be able to measure the path of the Milky Way simply by observing the gravitational measurement at various points of the Earth - points that correlate with the Milky Way overhead should read weaker than points that correlate with areas of the sky that contain far fewer stars..
Of course they don't since such an affect would be immediately obvious to Earth gravity researchers.
Here is a gravity map of the Earth. The gravity field does not change hour to hour and it does not match the Milky Way. This image is produced by a NASA satellite, so I know what most FE'ers will say to that....well what I say, is NASA would have to model this accurately otherwise ground measurements would disagree and eventually the conspiracy would come unstuck.
So what this evidence implies is that in a FET model, Stars cannot explain the lesser gravitational pull at height.