Look, just don't hit your truck with a sledgehammer.
Recently, the folks at Edmunds took their very own 2015 Ford F-150 and hit it with a sledgehammer for the sake of providing a real-world example of what it's like to get the aluminum bodywork repaired. The answer is that not only is it more expensive and takes longer (these two facts are related), it even costs quite a bit more than the initial estimate. It was difficult to damage in the first place though, so perhaps this won't be a frequent problem.
A significant part of the cost was due to the fact that the entire taillight assembly needed to be replaced, instead of just the broken part. But this is hardly unique or even a very new problem.