So I have an award ticket booked from HKG-AMS on KLM in early Jan and in order to make it, I needed to book PER-HKG. I searched for cash flights but direct with CX was around Ł700. To get around this, I searched from PER to anywhere on Google Flights with a OW airline and found the same flight with an 11 hour layover in HKG then onwards to Kathmandu for Ł400 so booked this.

Two questions:

1. Will they have an issue with me boarding the flight in PER if it is obvious I have no intention of going to TIA? I read you can get a visa on arrival so hopefully I wouldn't need to show anything but if they asked for any hotel bookings or return ticket I would be screwed...

2. Will there be an issue with me having two tickets under the same name/passport number out of HKG on the same day? The KLM flight leaves first so my hope is that I can just abandon the TIA leg in HKG and become a no-show for that flight.

Any guidance appreciated...

Google "skip lagging".
Will you have checked bags? They will be sent PER-HKG-TIA.
The HKG border officials will not be expecting you to cross the border. Remember HKG is China: not a western democracy.

PER-HKG-TIA and HKG-AMS on the same airline? (CX?)
A reasonable chance the software will pick you up as passenger on the same day with impossible flight?

thanks - this is helpful...PER-HKG-TIA is all with CX but HKG-AMS is with KLM. My plan isn't to cross the border but to go through connections and when they ask for a boarding pass to show the HKG-AMS boarding pass instead of HKG-TIA... that would be acceptable right? or would that cause me issues...

Will you have checked bags?
Would not expect CX to interline to KLM on separate tickets.
In my view what you are planning/hoping is high risk.

Nope - hand baggage only.

What bit is high-risk in your opinion? Urgh...nervous...

If it's obvious that you have no intention of going to TIA they will absolutely not let you board. Also, if it's obvious that you can't enter TIA they won't let you board.

The question is, what will they ask for, and will it be obvious to them?

A lesser concern is anything that CX may do after the fact (invoicing you for the money you owe them, banning you from future travel on their airline, reporting to the Chinese authorities that you may be attempting to illegally enter HKG). These all seem pretty unlikely but I would not totally discount them.

I am assuming you're holding an Australian (or a UK?) passport so please accept my answers on that basis.
From an immigration perspective, you should be fine. Timatic lists visa-on-arrival as an option, which is what airline staff will check. It doesn't show any requirement for a return ticket.

No, it won't be an issue assuming - as you've said - that you are travelling with carry-on only (otherwise your bags will go through to TIA).

There's nothing to say pax can't cross the border during a transit in HK (assuming they meet the entry requirements) and plenty of people do so every day.

I don't foresee this being high risk for any reason other than potentially p!ssing off CX.

The skiplagging component is the only thing to be concerned about, though the consensus seems to be that it won't pose an issue with CX as long as the OP doesn't make a habit of it. The OP is not attempting anything illegal with what's being proposed here (from a border perspective).

Thanks - this is super helpful.

Only one follow up question then, once I get off the plane in HKG, do I go through connections on my KLM boarding pass? I assume so but selfishly would like to go through on TIA CX ticket so I can use the CX First lounges...I also get that this is a bonus so would rather not use if it means evade the HK border police!!

Yes and if you want to use the KTM (Tribhuven) BP for Flounge access, you can.

would it not raise suspicion if I cleared security with one boarding pass and entered the lounge on another (that technically hadn't been used to clear security)?

Don’t think the systems are linked.

And plans change (starting to sound like a Sun Life commercial).