The issue I see with the OP (true tiling) question is not that we embrace yet another of the American suing culture, but how many qualified tilers - and with 39 years of experience I may be bold enough to include myself - are actually 'Qualified' to install 900x900mm tiles.
As new developments/technology such as fast set adhesives, underfloor heating, screeds and and very large format tiles all become the new norm, what training do any of us take to ensure that we are capable of delivering the safest installation.
As has often been stated on this forum, just because you have fixed tiles for years it doesn't mean you can turn out a good job, and for those who do - you still have no recognised qualification (as a Grandad I have NVQ 2 ).
If you want to drive on the roads, you have to have a license and that costs money.
If you want to belong to a golf club, you have to become a member and that costs money.
So why not pay to be assessed every year on all issues from Health and Safety to the latest product developments and receive a level of competence certificate which can be used to promote your own business.
It may not have any bearing on whether you can actually fix tiles to an acceptable
standard, but at least you should have the knowledge to do the job properly and if this was a pre requisite for having an insurance policy then the customer may have the confidence to offer you the contract.
Now all we have to do is educate the customer to do the required homework before instructing a 'tiler' before the commencement of a project.