Should Users see ID's?

[i00]

The xxxx-xxxxxxxxxxxx in mine is the start of the GUID ... and I am yet to have a conflict (would also have to happen within the same millisecond)

Yes, a big part of this GUID discussion is off-topic, if not interesting.
A proper GUID algorithm uses a lot of machine-specific information for a large part of the GUID.

...Also this is incorrect... it only uses the MAC address - and the chance for duplication is actually quite high if you use a VM for eg with the same MAC address as another on another network... and yes this happens (Hyper V I am looking @ you!)...
That said I think that this is a security flaw as it also is reversible!... for V1 anyway...

... .Net and M$ generally use version 4: 5B815BB3-46D4-4E60-94E3-2505AF516598 ... which is PURELY RANDOM BYTES!

... So you would have a 1 in 18446744073709552000 chance of a duplicate PER ms ...
This is actually effectively LESS chance of a collision than the MS one (with a lot of data over time); as that will have a 1 in 21267647932558654000000000000000000000 (1^31 ... I took the version chr out since this will always be the same) .... but this one is against the entire dataset... not just ones in the millisecond!...

Also with the M$ method you will have the issue that GaryMazzone mentioned, basically non-sequential GUIDs as keys are really bad for clustered databases performance-wise (with a lot of data at least).

Kris