In fact, the GPSR will give you warning of every proximity alert that you have loaded into it, according to whatever alerting criteria you have set both when you loaded the Custom POI file (e.g. how close to the POI you want to be when you are advised of it) and what criteria you have set on the GPSR itself (alert me, don't alert me, whatever).
Custom POI's are used for many purposes besides speed cameras. One forum member here uses them at work to alert HGV drivers that they are nearby LPG filling stations. Police in the USA use them to detect nearby donut shops.
If, when you are constructing the Custom POI file on the computer, you specify a speed to be associated with the POI, the GPSR will assume it is a speed dependent location (radar camera), and you can then set the alerting criteria for speed dependent Custom POIs as you wish - alert me all the time, don't bother me, or alert me with a persistent tone when the vehicle speed is higher than the speed associated with that POI.
There are quite a few variables that the GPSR owner can control so far as Custom POI alerting is concerned. It's important to comprehend that these variables can be controlled in at least 3 different ways:
1) How you construct the datafile - meaning, if you associate a speed with the POI.
2) What criteria you set on POI Loader (the application used to upload the data file to the GPSR) when you do the upload - warn by distance, or warn by time to station.
3) What preferences you set on the GPSR itself.
This is one area where the user needs to carefully read the documentation that comes with both the GPSR and the POI Loader program, and then experiment by making several different uploads, and observing how the GPSR operates. Please note (it is VERY important that you comprehend this) that when you upload a Custom POI file with POI Loader, it erases all Custom POIs that were there before. This is, in practice, a good idea - it keeps life simple - but can catch the user unaware if they have not read the documentation carefully.
It took me about a week of experimentation, and about 6 different uploads, before I became comfortable with how the function works and was 100% confident that I had it working the way I want. It's not a steep learning curve - in fact, it's simpler than constructing a route - but the concepts are new, and this is why you have to fool around with it a bit in order to get fully comfortable with it.
Lastly - there are many options available to the user when it comes to constructing the data files (comma delimited text files) that contain the Custom POIs. You can make a very simple file, or you can make a set of very complex files that have different visual icons associated with different types of Custom POIs. Data file construction is a bit like using a word processor - you can write a really simple letter that has right and left margins, or you can construct very elaborate documents that have embedded pictures, tables of contents, indexes, hyperlinks, etc.
Michael