I am afraid of this as well. It's easy to make mistakes and current software doesn't really offer assurances. Right now I sometimes visually compare source & de

I am afraid of this as well. It's easy to make mistakes and current software doesn't really offer assurances. Right now I sometimes visually compare source & destination directories. Like literally, make the windows the same size and scroll through them so I can notice if anything has visually shifted, which tells me files are missing. That's how I found some missing RAW files, but turns out those were taken on the fuji's auto settings which desn't store RAW even though I have it set up to take JPEG+RAW (many such idiosyncrasies with these cameras). I then almost had a heart attack when I realized that my camera filenames did a roll over from 9999 to 0001 and I wasn't paying attention. Luckily there was no overlap in that directory, but I could've easily clicked confirm to replace my earlier photos with new ones (DCIM better be replaced with something better soon).