Shamir's Simple Sharing Scheme - preventing partial recovery of data In SSSS, if you recreate the original secret with one of the decoder inputs being slightly damaged (e.g. one or two chars incorrect), you receive a slightly damaged version of the original secret. So if the original secret was "Abraham Lincoln", decoding using a slightly damaged input might still get you "Ab%aham Lincoln", for example.

What's the best way to encode and decode the secret, on top of SSSS, such that any variance at all in the inputs causes the decoded secret to be completely useless?

One obvious way would be to encrypt the secret before using SSSS. Are there any alternatives? In particular, any alternative that would not require each user to have a final decryption key (for decoding the secret that comes out of SSSS) as well as their SSSS decoding keys?
With SSS you are sharing field elements, so if the secret to be shared is larger than one field element, you are going to have to break up the secret somehow and share the parts. I am not aware of any standard method that allows you to make the sharings dependent on one another. Probably the best way is to encrypt the secret with a key and then share the key (using Shamir) and the encrypted secret (e.g using an appropriate erasure code) and store the share/fragment parts at different locations.

Note that this is not a problem of SSS. In SSS if a share is slightly corrupted it cannot be used in reconstruction. 

You could also pick a field large enough for your secret.