Moving Drive from S to FS?

Can I simply move the hard drives from my Drobo S to my new Drobo FS, without reformatting?

No unfortunately you would have to have the S and the FS plugged in and manually move the data over.

Can we please get a way to tell the drobo to preserve data on an inserted drive? It would be really nice to be able to insert a drive with a ton of data into the drobo and have it show up (it could prompt you to select which share to add it to) rather than having to go out and get another HD dock and then transfer it over. Maybe have an option that lets you prep for this by telling the drobo to put all of share x onto drive Y and ready it for ejection, so you don’t have a distributed data issue.
This is also very important if the drobo itself (not the drives) were to die, so you could just get a replacement drobo and put in your old drives. As it stands now, I have no idea if you could even get your data back, since it is distributed oddly across the drives.

Sounds like you’re asking for JBOD mode on Drobo.

As for if your Drobo chassis dies, you can just migrate the disk pack into a new Drobo chassis and your data will be there.

My understanding of how the drobo works is that it formats automatically and without override on insertion.

Drives only get wiped if they were in a previous system (tower, other raid device) and there is data on them.
Or if the drives are not part of the current disk pack of your drobo.

If you are moving a diskpack from one drobo to the same drobo, your data is NOT wiped.
Or migrating your diskpack from one drobo to one that can accept migrated diskpacks your data is NOT wiped as well.

But say you have a disk from a drobo and you want to add it with it’s data intact to an already active drobo. My understanding of what you just said is that even though it came from a drobo, because it has data that is not part of the diskpack that is in the destination drobo, it will get wiped.

Also, I maintain that it would be nice if there was a way to tell the drobo to integrate data from a drive you insert, rather than wiping it.

That is not possible since that drive you want to move is not part of the current diskpack, then yes it would be wiped of data.