Question:
Once again, a driver has gotten him/herself in trouble and probably lost their job. Same applies to O/O.
Driver allows significant other or nephew, niece, son, or daughter or just someone wanting to drive-to-drive their truck. Things go south and the state police or local police are present.
Example 1: Mall parking lot, which by definition is a "Highway", driving the CMV. Car pulls out and oops a fender bender. Nothing significant, however, a police report is filed.
Example 2: A family member or friend wants to know what it's like to drive a big truck, so the driver obliges the request. Ooops state police see whose driving and for what ever reason pulls over the truck.
The carrier now has at least two critical violations:
1. No driver qualification file for the driver
2. No pre-employment drug test for the driver
3. Perhaps using a driver with a suspended, revoked, or wrong class license. In Example 1 the driver only had a learners permit and the licensed driver was inside the mall making deliveries. In Example 2 the wife's CDL was suspended for an unpaid ticket. Imagine that...
In any case regardless of whether the driver turns in the report or accident to the carrier a police report exist. Therefore, the US DOT knows.
Now, if the driver or O/O hasn't already been terminated, what do you think will happen after the DOT starts asking questions? Does hit the road Jack come to mind? If not then you had better examine your employer's desire to appease the DOT by correcting the violation so it will never happen again. Not to mention the CRITICAL violations the carrier now has against them for your actions.
Be safe folks and NO, it's not your truck to do as you please."If men were angels...No government would be necessary."
51st Federalist Papers
"Nichols' Fourth Law says, "Avoid any action with an unacceptable outcome"

Answer:
Isn't that strange. Joe Smoe driver 1000 miles away from his terminal lets flaky jake drive and the carrier who hasn't a clue and couldn't stop it for any reason gets "CRITICAL violations ". Some of those rules are just plane dumb.

Answer:
The carrier must establish a written policy informing the driver of company policy and the consequences of disobeying those rules. Once the carrier has set a disciplinary policy and followed their policy, they have reduced their culpability.
Otherwise, the carrier bites the bullet for failing to have a company policy informing the driver of the consequences for his/her actions.
Carriers need to weigh their options when they hire a warm body to fill the driver's seat. If the driver doesn't have the smarts to do the job properly the driver shouldn't be in the driver's seat.
As far as the driver goes, with the requirements a carrier report safety violations to prospective employers, the driver will have a hard time finding a good job.
To paraphrase Pipeman, "Truck smart."
Be safe."If men were angels...No government would be necessary."
51st Federalist Papers
"Nichols' Fourth Law says, "Avoid any action with an unacceptable outcome"

Answer:
Forget "Truck smart." if they dont have the common sense to know better nothings going to help them.

Answer:
Excellent post JQP. This little sentence applies to just about everything in trucking:

The same company that lets stuff slide with a wink and a nod wil NOT stand behind you if get in trouble. Their best defensive business decision is to fire the offender and pull out all the evidence why they never gave you permission do do that and they sure ain't giving you another chance to make such a foolish decision. "Yikes, we're as surprised as you!" and "He signed this form saying he'd follow all the rules which includes never letting anyone else operate his assignd vehicle...." "This is obviously an isolated incident...we don't want guys like this working for us."
Look at these things from the carrier's point of view. What course of action is in their best interests? That's what they'll do. Sadly, in this day and age, anything else -- like going to bat for an otherwise competant employee who gets caught -- is considerd irresponsible management and a possible criminal violation of their fiduciary responsibility to their stockholders/owners, not to mention the regulatory agencies, insurance carriers and other liability issues...