I have been installing flooring for over 30 years and I have never left a jobsite without cleaning up,(broom clean), my work area. What if the homeowner was to have small children or pets in your work area,(or the aforementioned Family Room), after you left for the day? Hope the install company has good insurance...
I also find it very unprofessional that anyone would leave a beer bottle on the jobsite.(Found there or not.) Beer is good, but beer on the job isn't! Here's a scenario for you:
The job is completed and you left there with a big pat on the back and a hearty thank you from the homeowner. You get to work the next morning and your boss tells you the homeowner refuses to pay their balance on the job because you were drinking on the job and "We have pictures to prove it!".
Where do you go from here?

Beer on the Job site....NO WAY! I keep Ice Cold Beer in a frig at the shop, and my guys know I don't care if they have one at the end of the day, but not out on jobs. Tell your concern's to the store. It is real possible they don't know about this, and trust me they would be greatfull you letting them no. I am sure they don't want to lose a sell over beer & a mess.

One beer hardly exhibits a drinking problem. I'd say call the owner of the company and tell them you found the empty beer bottle on the job and you do not want drinking in your house period..

QualityFloorCo I know your new on the site as I am But you should look at when the post your answering was posted and last replied to. You could save yourself a lot of time. this one was last posted a year and a half before you posted.