Maître de Casson is not Banksy
Maître de Casson isn't Banksy
There is no connection between Maître de Casson and Banksy.
All so called "proofs" do not prove anything.
It's true that Maître de Cassons nickname was Bank-Si, also it's true that he changed for several times his name from originally Edmond Safra II., however the british graffiti artist Banksy and Maître de Casson are not the same person.
This sketch by Maître de Casson trying out some new nickname similar to Bank-Si and looking like Banksy does not prove anything. It’s a coincidence.