No, this says that if no member is ON (i.e. if they’re all either OFF or NULL), OFF is returned.
I wouldn’t use the OR(…) logic anyway as in terms of presence detection, you should be aware that sensors can produce false positives, so I’d suggest to check for a quorum such as 2 (means: have at least 2 sensors ON before you consider this to be a a signof presence).
To get there, you cannot use built-in functions anyway but need to program your own (i.e. a lambda).