No it doesn't, unless it's a knife and a small child.
Replace USB drive with knife, and GF with small child, and laptop with body part, and you might have a case for the OP being responsible in some way.
But flash drive + adult human + laptop? No.
Are you kidding here?
We're not talking about death. We're not talking about hurting kids. We're talking about 'puters.
Would you hand a novice the media the OP did and just claim whoopsies when the novice rebooted with the media still in the system?
Your scenario vs my scenario:
knife : usb drive with unattended install
baby : novice
body part : computer
Somewhat similar in setup, the only difference is that one is likely to cause death or serious physical injury, the other is likely to likely to cause data loss and a waste of someone's time.
I damn sure would not hand a loaded gun to a person who has not used guns, and I would also not do what the OP did. As someone who has known about the use of guns for quite some time, the first thing you learn is act as if the gun is loaded at all times. Never hand someone a loaded gun without making damn good and sure they are aware that it is loaded.
In the OP's case, if he has the capacity to create an unattended installation media, he should also have the capacity to check it and inform others he intends to loan it to. While it was not his intent to hand out the loaded gun, if he created it, he should "unload" it when he is done using it. At the very least, he should have put it away somewhere for future use if needed. You don't put something like that back with all the misc. other devices you have for the reasons discovered by the OP.