Of course there have been ample warnings, including the handing out of leaflets detailing the unlawful offenses. Many people were ticketed and arrested at border crossing protests, including 11 members of a splinter group, in posession of 13 long guns, ammunition, body armor and hand guns.
The Ambassodor Bridge, accounting for ~30% of the cross-border land trade has since been cleared. The damage is estimated at above $500M. Damages at border crossings in Alberta and Manitoba have been estimated at 48 and $73M respectively.