Joe L, i removed your dub-post. There's no need to post the exact same sentences like 2 hours later.
Just reinforcing with an external reinforcements won't stop the cracking. First things first, you gotta get rid of the crack, THEN reinforce. Going to a workshop (or someone who welds aluminium) and let that/those crack/cracks welded, it's cheaper than getting a whole new scooter.
Here's what i had when it started to crack:
And below is the result of going to a workshop - crack's gone.
After loosing the crack, then you should start reinforcing the deck, if you want to.