We version (localize) projects all the time, so I thought reasonable logic for seeing whether a string is empty is to check whether its trimmed length was greater than two, allowing for two stray characters that show up all the time in content. For example, someone who's not sure how to translate something would type "??" in a field. So, {if $slide.title|length>2} ... This worked for 4-5 languages.

Then our Chinese (Mandarin) division called and asked me to look into buggy behavior with their translations. Turns out a whole sentence got translated to ... two characters, and wasn't showing up.