While ruby does not have a strict mode, I'd actually like such an option. In ruby, you can't declare local variables or instance variables. When developing ruby code, I typo variables very often, and ruby is very unhelpful in finding these bugs. (I sometimes also use the same local variable twice in the same scope, a strict mode would help warn me about this too.) I think it might theoretically be possible to add a strict mode, but of course you'd first have to invent syntax for declaring variables.
