NB as it seems, Squeak does compile methods with unknown pragmas where as WV throws an error if one uses an unknown pragma (which typically happens because of a typo).
Yes, Squeak does not require pragmas to be declared. The compiler however throws a notification if you use an unknown selector and offers you to change it, similar to what it does when you use an unknown message send within normal code. In my opinion this is much more Smalltalk like than requiring a static declaration of pragmas.
Lukas