In reality, it was preferential to have infantry in front of the armor. In most historical cases, sending armor ahead of infantry resulted in the armor getting devastated by anti-tank fire. Being inside an armored vehicle, one couldn’t hear the enemy and certainly had a hard time seeing small units that were waiting to ambush.
Possible solution: It would be best if you were using a hex map with numbered hexes (like battletech). Both sides can write on paper where they are deploying their units. When a player wishes to move a unit, the unit is revealed starting in the hex it began in. If a player uses the unit to fire it is revealed. This way, if your opponent rushed armor onto the battlefield then they would suffer the risk of taking anti-tank fire from a very close range, and that would mimic reality. Perhaps enemy positions could be revealed when you’ve moved one of your units into an adjacent hex.
Ambushing is such a basic element of ground battle and I regret that it wasn’t included in the rules. I guess thats what house rules are for.