When files are trashed they loose all the information that GIO had stored about them
This might possibly be a bug. When files are trashed they loose all the information that GIO had stored about them.
For example, adding some random emblems to a test file and trashing the file makes the emblems disappear:
echo 'This is a test' > test.txt
gio set -t stringv test.txt 'metadata::emblems' \
'emblem-important' 'emblem-favorite' 'emblem-default' 'emblem-mail'
gio trash test.txt
Same goes for the metadata::annotation
key used by Nautilus Annotations.
--madmurphy