The highest and best use for a GPS may be for an Alzheimers patient or someone who frequently wakes up soused with no idea of where they are or how they got there - a map is only of value if you can see where you are (trail junction signs) or know where you started and which direction you went.
It is always possible to enter incorrect coordinates (human error). However, an error in transferring the coordinates is most likely going to result in a location which is not confusable with the desired peak. And if you read the wrong location off the map (and enter its coordinates correctly), it is a human map reading error which has nothing to do with the GPS.
There are a number of ways to get bad coordinates in a GPS unit:
* The preloaded GPS maps are wrong, the bump that my sister's GPS showed as the summit of Snows Mtn was one bump too far beyond the true summit
* You get erroneous coordinates from a buddy, a website, etc. and enter them correctly
* You get correct coordinates and enter them erroneously - transpositions are common on geocache locations
* You digitize coordinates from an inaccurate paper map - one of the 3 bumps shown for Mt Cabot apparently doesn't exist
The issue is not one of who's to blame, it is that the device may not correctly indicate the summit even if the electronics function perfectly.
(Remember, you are on or near a peak which is likely to have a good skyview and thus good signals.) If you get a bad location (ie a large error), it is very unlikely to be on a nearby peak and it is likely to jump around unrealistically.
The poster must have limited experience with spruce/fir summits
On the bump S of Wildcat one could go from 6 satellites to 0 in a few steps. I believe the original post was referring more to people who stopped on the wrong bump maybe 1/10 mile away in thick scrub rather than somebody who climbed the wrong summit 5 miles away. This is exactly the sort of conditions in which the signal may be poor and coordinates jumping all over, within the error range he's talking about. Let's just say that chasing a jumpy signal in thick scrub is not an effortless use of a GPS.
And many peaks have multiple coordinates for the highpoint which I doubt
anyone enters in a GPS.
This is essentially the same problem whether you are using a GPS or not.
Not quite. If you have a map and study it, hopefully you will see the multiple bumps while if you just download summit coords from somewhere there will probably just be one set and you will not know of the others. Can you show me a website with coords for 3 bumps of Mt Cabot or 2 of South Carter?
(Paper maps can be incorrect too - the WMG map shows S Kinsman at what most people agree is the wrong place.)
One approach for those who do not wish to use a GPS to navigate but wish to verify that they reached the proper peak is to carry a GPS to record a track without consulting it during the hike. One can then check after the fact. However, this reduces the risk since you know that in an emergency you can always use the GPS.
That only makes sense if your objection to GPS is purely philosophical, as by running a track log you are exposing the device to far more risk of damage and loss than if you just take it out of your well-protected pack only to check the coords once you think you are on the summit (or if you think you are lost and need a hint.) Most non-users are probably less from philosophy than from expense or the hassle of obtaining and loading coords.
If you have a radio or cell phone, there may be merit in carrying a GPS in your first aid kit only to report your location if injured. As cell phone triangulation improves, that may become unnecessary.