How so?
It would be perfectly feasible to require those wanting to strike to register their intention in advance. If they don't register their intention, they lose the employement law protections if they nevertheless go on strike.
And if they register their intention, they won't be paid if the union withdraws the strike less than (say) a week beforehand - unless the employer agrees otherwise.
Yes, it would be a change and require a little bit of administration. But nothing impossible, certainly not when the government is in a mood to rewrite the law on industrial action!