PAXboy's story has intrigued me. I wondered, if SQ has denied him permission to board, what possible grounds could they use to do so? ie, where in their T&C does it allow them to do so? So I had a look at their T&C, and this is what I think they can use:
Conditions of carriageARTICLE 14. ADMINISTRATIVE FORMALITIES.
Para. 1. General.
The passenger shall be solely responsible for complying with all laws, regulations, orders, demands and travel requirements of countries to be flown from, into or over, and with Carrier's Regulations and instructions. Carrier shall not be liable for any aid or information given by any agent or employee of Carrier to any passenger in connection with obtaining necessary documents or visas or complying with such laws, regulations, orders, demands, and requirements, whether given in writing or otherwise; or for the consequences to any passenger resulting from his failure to obtain such documents or visas or to comply with such laws, regulations, orders, demands, requirements, rules or instructions.
Para. 2. Travel Documents.
The passenger shall present all exit, entry, health and other documents required by laws, regulations, orders, demands or requirements of the countries concerned, and permit Carrier to take and retain copies thereof.
Carrier reserves the right to refuse carriage of any passenger who has not complied with applicable laws, regulations, orders, demands or requirements or
whose documents do not appear to be in order, or who does not permit Carrier to take and retain copies thereof.
So if SQ should argue that PAXboy's documents do not
appear to be in order, that might work.
The next hypothetical situation would then be, if PAXboy was able to show them the official Singapore government website that says that he does not need the additional passport validity for transiting, would they have relented?
But as PAXboy says, this is all history that has ended without tears. I am just having a bit of fun thinking through hypothetical scenarios.