In 1986, when we were first in Thailand, we bought a rather large teak spirit house, had some of the decorative trimmings knocked off it and stowed away separately, the sellers (at some market place, no idea where...) taped two cardboard boxes into one, and ... of to Belgium. So we hoped!
We'd booked the train to Bangkok and, at the given moment, boarded the train with our luggage. Or so we thought: the spirit house was too big to get through the train's passenger door! (I guess, in those days, they were little trains!). Fortunately, railway personnel clarified we could stow the box in the last wagon, the parcel compartment.
In fact, even though we'd booked to Krung Thep, we were going to get off the train at Ayuthaya, and we thought we'd made that clear to the train attendant. Arrived at Ayuthaya, we got off the train and, as I walked to the back wagon, the train jerked off direction Bangkok, without me having retrieved the parcel.
So we made profuse use of gestures, dismay et.al. to explain to the station attendant that our...spirit house...was still on the train. Dismay all round, never mind, no problem...some one phoned somewhere...and told me to come back to the train station next morning at 10 AM. We were, I must admit, extremely sceptical and feared that that would be the end.
Next morning, at 10 AM sharp, the box was in the station office. Whether the fact that it was a -lost- spirit house had anything to do with it, we will never know.
This is but one of several indications that Thailand can be very efficient!
Our return flight was Thai airways. Not a cent extra luggage was charged...that was 1986, of course.