Extremely unprofessional. Leave parcels at front door in full view of the road, knock and then walk away.
We have a video doorbell, and the don't even press that, so if we're upstairs or in the garden, we don't know they've been.
Occasionally, they'll leave the parcel in a more "secure" location and toss it over a 7 foot gate, without bothering to leave a card.
Many is the time we've found parcels that have been there days and are soaking wet.