Spent the lunch hour here listening to a gentleman from Trimble discuss GPS, GPS myths etc… Some Common GPS myths:
WAAS will work everywhere
GPS will work everywhere
All GPS receivers are the same
You can use a rec. GPS for GIS data collection
US coast guard beacons are coastal
Selective Availability is still on or will be on again
You can get an accurate position with less than 4 satellites
Other people can track you if your GPS is on
All basedata is accurate
Aerial or satellite imagery will replace the need for GPS
Datums are not important when collecting GPS
WGS84 datum is the same as NAD83
Vert accuracy is the same as horizontal accuracy
See also http://www.trimble.com/gps/index.shtml