Sanitizing the field key may cause unwanted behavior

[villesiltala]

The inner_set_key() method is used for all keys set through the Field constructor. It sanitizes keys with the WP sanitize_title() function. This is necessary when the key is created out of a label text, but it might not be wanted if the user sets the key explicitly.

Could the sanitizing be done only if the key is created out of a label text?