Build Your Own Tank

I have lots of questions about this story: a college student builds 1/2 scale German tank for use playing paintball.

1. College students have $10k laying around to build tanks?
2. Why the dickens did he build a Tiger I when he could have built a Tiger II?
3. What's the best way to make sure none of my sons build a tank when they're supposed to be doing college-y kinds of things?
4. What kind of clearance does it need? Because my paintball field has a lot of stumps...