What’s being altered? In reality, OCs restrict access to common property all the time.
Do they do it “all the time”? Yes, they may restrict access to pools and gyms at certain times, but if there has been an expectation that the pool would be available most days for most of the time, shutting it down for several months is a significant factor.
As long as they don’t block 24/7 access across common property to the lots and do it fairly there’s usually not a problem.
“Usually” is a bit of a weasel word. There is a potential problem when there’s a chance that someone might reasonably object.
To take an extreme example, if the committee blocked access to your car park while essential maintenance was being carried out, residents might be irritated but would accept it. But if they were to block access from, say, midnight to 7am at weekends, because of noise and security issues, some owners would be up in arms.
As I said, I am not sure where the Tribunal would fall on this, but I do think there’s enough of a grey area that if an owner was so inclined, they could make a fuss.