If you have users who think it's cute to alter the search type by hand, you can end up with a whole lot of server errors being logged because the search type trying to be stored is more than the 25 characters allowed by the schema...
Fixed (locally). There isn't really much significance other than the error log.
However, in this situation, it doesn't make sense to even have the search type. The type can be used to do a content-type-specific search. If it can't find the type, it automatically flips back to a global search. As such, I believe it makes sense to wipe out the type in that case.
Yeah... Agreed it didn't matter much other than server log. In my case, it was a script kiddie that ended up putting thousands of entries in my server log... Which sort of rendered the server log useless because I wasn't going to look through them all in case any legit items were logged.