There were good old days when smokers walked free..... I'm of the opinion that there must be a smokers room in every airplane probably a lav converted for the purpose.
Toilet flush liquid is inflammable and it's only a disaster waiting to happen as some passengers are not educated enough to understand the facts.That is the reason regulations demand the toilets be fitted with smoke detectors.
Airlines are forgetting they still are in the hospitality business and no smoking regulations on board are causing more problems than one.