Porcelain laid on sand and cement? - Tile Advice

[Slippery]

A friend of mine (who is a great brickie) laid his patio the other day, he used a wet bed of sand and cement and back buttered the tiles with a sand and cement slurry.
He didn't use a decoupling mat or cement board, just a MOT base.
He does a lot of stone paths and patios like this but I have my doubts as to how this will stand the rain, sun and frost.
What do you guys think?

 

[Slippery]

 

[Tile Marble Granite]

View attachment 127629

It looks great. That porcelain will come loose, it is just a matter of time. One by one. Hope I'm wrong!

 

[Ajax123]

Can't see the need for uncoupling outside. In fact in many cases it would seem counterproductive. Can't see a reason why this should fail anymore than any other install. Looks nice too. Might get a bit slippy though.

 

[Slippery]

Thanks for the replies, just goes to show opinion is divided, I hope it doesn't, he's a nice chap and very talented.