I think theres a MASSIVE difference between a cheat night and a treat night. To me theyre 2 very very different things. When I did WW I always saved points up for my wi day and if I lost I used them on a Chinese takeaway etc. That was my TREAT for a good week. It was something different but completely within the plan.
A cheat to me would have been (again using WW as an example) having used my points for the day but having something else to eat anyway - going off plan
2 totally different things IMO. Absolutely nothing wrong with a weekly TREAT but a weekly CHEAT - well thats when your diet goes out the window