A few months ago I was building a router table and asked about putting a
miter slot into it to use with a sled.
Several people said they just ran the sled against the fence and found it
worked out well. It made sense, so I went that way.

The table is fine, but now I am making the sled and am not sure it still
makes sense. On some cuts (say a tongue and groove frame) won't the router
bit hit the sled? I suppose you could put a spacer between the sled and
workpiece, so the router bit is too high to hit the sled, but that seems
like it would ask for inaccuracies.

Am I missing something here?