I have to agree with BB forks, no one should consider themselves as correct if the take something from someone with no intention of compensation to the original owner, and with the intention (or does) to sell that thing to someone else.
If it was a lamp, a lawn mower, a birdhouse, or other tangible object, there would be no question that it was theft to take, with demand and without compensation, from someone to sell to someone else.
I don't see (and am pretty sure a company attorney will agree if they are asked their 'honest legal opinion') how that changes when it is something intangible, like someone's time. I think almost any attorney in the USA will agree that is a form of (and the definition of) theft. I am also aware that one of the most common reason most attorneys get their license suspended to practice law or get fined by the bar association, is actually from "double billing" where they have billed more than 1 customer for the same thing, their time. (you also can not legally sell the same exact object [time or lawnmower] to more than 1 party, and expect to be paid by both parties for that 1 exact same object).
All that said, as an individual, and owner of that object (your time or your lamp), you may freely dispose of that object as you see fit, so, if in your desire to be a better representative of the company to the customer you give the drive time to the customer, that is YOU* (not the company expecting or demanding) giving away your time (not the _company_ -selling- your time and demanding you give it away to the company), just the same as if you studied the standards at itsdf dot org on your own time at night to better understand forklift design, as compared with the company expecting/demanding you take an online training course, where the company should expect to have to compensate you for your time.
* that said, since your time driving to the customer is something the company could/should have sold, you will be undercutting (and in fiduciary conflict with) your company if you give away your billable labor time.