BTW, I haven't looked thoroughly into that Allegiant thing yet. But I wouldn't be surprised if it wasn't because the judge simply found that one of those two conditions detailed above wasn't met. This was off your link though --

"A federal judge in Las Vegas has issued an order barring Allegiant Air pilots from going on strike while mediation is under way in their labor dispute.

Judge Andrew Gordon ruled Friday that International Brotherhood of Teamsters Local 1224 can't strike in order to gain leverage over the airline while both sides are in mediation under federal law."

From this, I'd say that, as per my hunch, the Judge ruled the strike illegal on the basis of condition 2 not being met in that the union had not completed a/o attempted all manners of resolution yet since mediation was still underway. If the teamsters called for a strike prior to going all the way through the process then they must have some pretty shoddy lawyers.