Here's another example: Alice asks Bob to attack in the morning. Bob accepts. But Eve doesn't let Bob's acceptance message to get to Alice. Alice waits for some time and asks Bob again to attack in the morning. Bob accepts. But message still doesn't reach Alice. If message does reach Alice before the attack, it's a win. If not, i.e. Eve holds messages past the attack time, only Bob attacks, as Alice won't know if he will.
A sends "Attack at 5:00, send your plan"
B sends "Attack at 5:00, send your plan"
A sends "Attack at 5:00, send your plan"
B sends "Attack at 5:00, send your plan"
A sends "Attack at 5:00, send your plan"
B sends "Attack at 5:00, send your plan"
Let’s say the last message in your example is dropped
B would have 3 acks from A while A only has 2 acks from B.
Will A attack? If not, B is left attacking on their own.
Similarly, what if none of Bs messages make it back to A? How does B know to attack?
I think it doesn't work because the problem becomes "when to retreat". It actually introduces a third state (attack; retreat; do nothing), where I might retreat today, and you do nothing.
Out of interest, if you set a time/date on when to retreat, how would the message look like, and how would you define confirmation for both parties?