Hong Kong seems to use a slightly modified BS regime. With BS1363 being the default standard. However, BS546 seemed to still crop up quite frequently, where as it's pretty much vanished in the UK.
The only worrying safety concern that I've come across with the use of NEMA style parallel blade plugs and Aus/NZ style slanted blades is what a Chinese friend of mine explained that she does.
If she can't find a NEMA style outlet, and only the slant-pinned type, she uses a pliers to twist the NEMA style blades into the 'correct' shape.
It just seems a lost opportunity not to have come up with a Class II version of the slant-blade plug too. It's a nice design as it's self-polarising.
I think BSI had the right approach when they went with BS1363 in the UK. The system was designed not to be compatible with pre-existing standards so it wiped them out very quickly and completely and has improved safety in a huge way. Ireland's adoption of BS1363 was for the same reason.
I find the piecemeal 'don't rock the boat' approach that has been taken with European connectors caused more problems than it solved. They've ended up with all sorts of potentially dangerous combinations.
At least the Brits had the good sense to recognise that their original system was completely nuts