Jetdriver,
You certain? For instance (and again, this is limited to the US, thus, for example only), American won't allow pax use of GPS at all, but Delta treats a pax GPS like a laptop. There is, however, one difference. Although Delta allows both laptop and GPS to be used above 10 thousand, it also allows the GPS (but not the laptop) to be used during taxi-in to the gate. Of course, neither may be used during taxi-out, climb (BLO10), descent(BLO10), approach, etc.
I checked the Sri Lankan website and found some PED info but nothing on GPS. Is your info specific to Sri Lankan?
Just wondering,
Dave