Actually CA, yes there was an exception to abstaining from blood. 1 Samuel 14:
31 That day, after the Israelites had struck down the Philistines from Mikmash to Aijalon, they were exhausted. 32 They pounced on the plunder and, taking sheep, cattle and calves, they butchered them on the ground and ate them, together with the blood. 33 Then someone said to Saul, “Look, the men are sinning against the Lord by eating meat that has blood in it.”
“You have broken faith,” he said. “Roll a large stone over here at once.” 34 Then he said, “Go out among the men and tell them, ‘Each of you bring me your cattle and sheep, and slaughter them here and eat them. Do not sin against the Lord by eating meat with blood still in it.’
It was a clear violation- eating of animal blood. The result?? They were told "Don't do it again."
Later in the account when Saul wanted to know why Israel was not being blessed and who was at fault, he or the Israelites it was revealed as him, not the Israelites who ate blood.