There's a chance they may not know who's got it. But I always take it to them as soon as they are in, and I expect the same. If it's left with you, you are essentially taking on the responsibility to deliver it safely and timely IMHO. We had one left with opposite neighbour once but we didn't get a note. Took him a week to eventually bring it round, that's rude
I think that's the point , if something misdelivered or left with a neighbour, and you are expected to ensure it is given to the original address, it could be construed as theft being in your procession, not apart from trespass , if you have no real reason to be there.
But that is extreme, as a postie ,I only had the right to walk to the delivery point by the most direct allowed route, i.e up the garden path,not across gardens or front lawns.
It will take a real 'jobsworth' to perdue such a case in point in law, but as it stands I don't and shouldn't accept parcels for someone else, unless there is a Verbal agreement.
But that comes from a former working life.
I am in the added situation where my upstairs neighbour is a serving Police officer, not that he would take umbrage, but he might.