score:4
A few years ago I answered the question whether an envelope can be checked in and researched whether minimum check in size policies exist and came up with a negative. I found this ancient flyertalk thread but they haven't heard of such either. I quoted
Some airports with a very sophisticated baggage handling systems have a minimum weight of what can be checked-in (don't know about size), I think it's something like 3 or 4 kilos minimum.
and
I once checked a cardboard box that was about 8 inches long, 5 inches wide and 3 inches deep. It contained an expensive corkscrew that obviously couldn't be carried on.
I conclude you will be fine since you adequately packaged it.
Upvote:1
At the baggage claim, sometimes I see plastic trays with relatively small items (e.g. backpacks). So there probably isn't any minimum checked bag size -- the airline can put your small item into a plastic tray to make it easier to handle.
Upvote:1
Keep in mind, airlines still have mail and parcel contracts so flying small items is not at all unusual.
Larger airlines also offer express delivery services such as Delta Dash.
The most possible, but improbable, oopsie is the baggage handlers mistaking it for cargo and putting it on the wrong cart.