Personally, I won't tile walk. I used to but after various mishaps and near misses, it is not worth the risk.
It's years ago admitted but I've once paid out over £300 to a customer for a single broken tile and as above, got blamed for all the others which then went into 'having to have' the whole roof replaced over the front door extention.
The job paid £8. The house owner, a real shark of a lady, threatened legal action and it came down to the fact that tiles are not meant to be walked on and I would liable even if it was one tile to make good the damage, and added to which, the H & S laws (at the time) were broken. Now the law is even stricter.
Apart from all that, I'd tell the customer and take whatever comes and not tile walk again. It only takes one slip.
Cheers