Aucun50, I do use brackets, but with a short code, they are not needed. It depends on the circumstances where brackets must be used. And you have RusselB's coding "pattern" wrongly claimed. He often codes it as such, for instance:

if aucun50 ison $chan { ... }

where parentheses are void. But there are times he DOES use parentheses and brackets side by side. There's no definite proof that, without using the brackets, will make your PC work harder. I'll take that as a hearsay.

P.S. If you've read mirc's help file, you'll find that there are many examples without the use of {} and usually they're a line of codes to show how an event works.