Empty strings in data fields do weirdness

[Jerald]

If you have a data field that's an empty string, bad behaviour occurs. Writing/reading to them does bad things.

[farteous]

Trying to create a data field containing an empty string doesn't do anything, creating a data field that only contains spaces (any number of spaces, as far as I can tell) becomes an empty string.
A bigger problem is that decrementing a data field that contains a string never deletes the last character.