I've done this type of tile tub 20 years ago and had the inspections office recently, reject it as tub which uses the shower lining fabric as it doesn't have a rating for the depth of water in the tub. I did the one 20years ago and never had a complaint, but jurisdictions just do not want to take any risk with logical extensions of current or old technology without study that will let them pass the buck .

This tub dates back about 7 years. We did not have a code problem with it, but were maybe just lucky.