zero keys in dropdown list

When creating a dropdown list from studio or by code, is there any chance to have a zero (0) as a key?

I tried creating dropdown entries with key 0 and a non empty value, but the value gets removed as soon as I save the list. 

I have debugged the code and found the following in modules/ModuleBuilder/parsers/parser.dropdown.php:52

$dropdown[$key] = empty($key) ? '' : SugarCleaner::stripTags(from_html($item[1]), false);

so every value with a key 0,'' or null gets removed.
What is the intention behind this behaviour and is there a possibility to make an upgrade save customization
to this code?

Thanks!