This has probably been suggested before, but I find when I make many sightings in a day I add them one by one into the iNaturalist app on my phone, and just pass by the ones I’m not sure about, intending to come back before I’m done and do more research to make a stab at an ID before clicking “Upload” (btw, I use Android now and I very much miss the iPhone option of being able to upload specific sightings! Feature suggestion #2 right there). Anyway, the point is, by the time I’ve added them all I find I click the Upload link and forget to review the ones I didn’t complete.
A simple warning saying “Whoah nelly, you have 4 sightings without any attempt at an ID. Are you sure you want to continue?” would prevent this.
I often see other iNat users - many experienced ones - uploading “something”'s, so I suspect I’m not the only one being caught out by this.
Sounds like a reasonable idea but if it was implemented there should probably be a setting to turn it off as some people do upload unknowns frequently.
I think some of the users with large observation counts have a habit of doing bulk uploads where they import dozens or even hundreds of observations at once and then go back later to add IDs, so the option to turn off the reminder would probably be a must for them.