Dishonest and untrustworthy.
Unfortunately I left my laptop and a folder in the flat on a table next to the couch. The folder was returned but the laptop was not. They were sitting next to each other so it is inconceivable that one was returned and not the other.
Of course the hosts assured me that there was no laptop left in the flat but the simple reality is that both items were left together and only one was returned. Returning the folder and not the laptop confirms that both items were left in the flat but only the less valuable item was returned.
No one means to leave anything behind but when they do it is extremely disappointing to have things so blatantly go missing.