I'm not sure if I'm more sickened by the thought of someone developing such a service or the thought that they are likely to be quite successful.
Update on 6/22/09
I thought about this problem a little more, and there's really a simple solution for the technically-inclined.
- Have the student produce an MD5 hash of the file before it is emailed or submitted to the professor, and have the student email the hash to the professor.
- If the received file is corrupted, the professor should produce an MD5 hash of the file. If it matches the hash from the student, he received the correct file, so the student's original file was corrupted. Let him bring in his laptop and show you how his file could be opened successfully on his machine since it won't open on yours. Probably he won't be able to, so give him a zero.
- If the submitted file's hash does not match the submitted hash, the file got garbled in transmission or the student did not email the correct hash. The student should just resubmit the file... eventually the received file's hash should match the original hash. If the student is not able to produce a file that matches the original hash, he's either incompetent because he did not properly create the original hash, or he modified the original file (which he shouldn't do if it's finished), or he's trying to cheat. Either way, give him a zero. (Wow, I'm mean!)