I can understand why people might not like the idea of storing multiple column values in one encoded field, but it does occur to me that this would be a great technique for passing values in a web app. instead of http://blah.com?field1=1&field2=5&field3=7
Bitmask all the values selected and pass them encoded
then decode on the page to values for SQL or whatever.
You get a lot of things here: users can't fish by inserting other values in the POST string; your POST string looks LEE7 (sorry...:-D); you have a shorter POST string.
Just my 2 centavos. Sorry it's off-topic, but hey.