I understand the point you are making ... but I am not sure at all that there are well understood and accepted "principles of worker's democracy" that obliges the individual to do anything. Even if they did, it would only be something which could be enforced as a type of contract. Nothing can be enforced by force or threats of force. (And I certainly don't agree that if those who wanted to strike are outvoted that they have to continue working - they are still perfectly entitled to make their own decision and, if they want, to withdraw their labour and no-one can force them to do otherwise by use or threat of force).
#you're missing something very large here, and I think it's because a) you have no class politics, or so it seems, and b) your politics, such as I have beern able to discern, are unquestioningly pro-state, -establishment and -status quo.
There is nothing which can legally bind people to respect a picket line. There is nothing illegal about crossing that line. There is something hugely immoral, wrong, loathesome about scabbing, and something VERY morally right about doing everything possible to prevent it; it;'s about community, in the workplace or wherever, and it's about loyalty to that cmmunity, that class, and the fact that that class, and your workmates, and your community, have an absolute moral right to your solidarity in their hour of need. Every working class person in this country understands this, everyone who lives in an embattled w/c community understands that, everyone who has reluctantly gone on strike understands this, and knows this very clear moral point. And that is why feelings about scabs run so very high, and i for one say 'fuck the law - you owe it to your comrades'.
tbh, you're a copper (or were) and I feel that the inevitable consequences of that job, and the dialectiical implications of a class analysis of the police role, means you can't help b ut see things in narrow legalistic terms - you're just never gonna have that instinctive feel needed for class solidarity. In the final reckoning, the cops ARE the repression tool of the ruling class.