@Dynamo Frokane
Honestly, I dislike both options. First of all, I would have the tank stop driving, make it into a fortress. Then, if they notice us, we can fight them off with our personal weapons. If they don't, then we continue on our way afterwards.
If they do attack, and we defeat them then we would have extra weapons and ammo. We could also have one of our number use their motorcycles as a scout. Lastly, after defeating them, I would then order that their vehicles be hidden so that we can recover them at a later date.
If anyone wants to say this in their post, they can.
Okay that seems fair you're going to wait it out and see what happens, I'll add that as a 3rd option. Give the orders as you see fit.