Comment by robotresearcher

You knowing the answer does not make a question silly.

It's not obvious to me that the Army won't do whatever it wants with you once you've taken the shilling. I was interested so asked Gemini, so subject to the usual LLM caveats, here's the reply:

"It is possible to join the U.S. Army and be guaranteed a position as a truck driver, provided you meet all the qualifications.

This guarantee is part of the enlistment contract. The specific job you're asking about is known as MOS 88M, or Motor Transport Operator.

[...]

What "Guaranteed" Means

When you have 88M in your contract, the Army guarantees you a slot at the Advanced Individual Training (AIT) for that job.

You will first complete Basic Combat Training (BCT), which is about 10 weeks.

After graduating from BCT, you will go to 88M AIT, which is approximately 7 weeks long, located at Fort Leonard Wood, Missouri.

During AIT, you will be trained to operate and maintain the Army's fleet of vehicles, including Humvees, light/medium/heavy trucks, and tractor-trailers.

The guarantee is for the training. You must successfully pass both BCT and 88M AIT to officially become a Motor Transport Operator."