So far, it’s blazingly fast — I mean, lightweight, and the file system shield doesn’t slow down the system, because the on-demand scanning speed is difficult to estimate — and, to my surprise, it didn’t raise any false positive as of yet!
Still, I wanted to make sure it asks before doing anything. As this configuration option is well-buried, here’s where it is: Settings → Active Protection → File System Shield → → Actions, then my choice for the 3 operations to be attempted, in order: 1. Ask, 2. Move to Chest, 3. No Action.
Don’t forget to configure the actions not only the first tab you see in the last screen — “Virus” –, but also “PUP” and “Suspicious”.