Let's talk about our Red Rush strategy...

There might be some nuances that should be considered...
Example 1: Red enters Blue's territory on day 7 with units moving at maximum speed 9 (let's say Blue has speed 11), and on the first day of the following week, they receive reinforcements, for example, dragonflies, and attack the opponent's main hero. The dragonflies skip their turns but provide the initial speed boost...
Example 2: Red receives a couple of immune creatures as reinforcements on the first day and attacks a hero who has Armageddon and enough creatures to eliminate everything in 2-3 turns...
In other words, the mere presence of a certain unit on the battlefield can radically change the outcome of the battle.

The described cases are quite rare and cannot be specifically planned for.
However, this can be taken into account and reflected in the rules:
1. casting is not allowed during the reinforcement turn
(which would also be fair when Red has magic left, but everything except the reinforcements is defeated: if you didn't preserve your regular troops, you can't kill – retreat!)
2. dismiss the hero if only reinforcements managed to survive in the battle (i.e., come to a situation as if there were no reinforcements in the army, and both would die in a massive battle)

i.e., reinforcements do not affect the outcome of the battle in any way, even if they are present in the army!
And most importantly, by accidentally attacking with reinforcements, Red does not suffer a tech loss in the game :) and also does not suffer from the inability to attack/the need to dismiss part of the army if the revealed Darkness suddenly shows an enemy weakling or a support village
and the issue of (non-)influence on the battle is automatically resolved))