I almost forgot this. Yes, BootCamp 5 under Windows 10 can screw up your hard drive.
The reason is the BootCamp 5 "applehfs.sys" driver, which does not work in Windows 10. It also causes other errors with Windows 10.
To overcome the issue, disable this driver after BootCamp 5 installation and use the free Paragon HFS+ driver for Windows 8/8.1 instead. As a benefit, you will have read and write access to the HFS+ filesystems using the Paragon driver.
I still have the bootcamp installation files on a usb drive. I've double checked, and there's no file named "applehfs.sys". I can download the paragon hfs+driver from the internet, but adding that file to the bootcamp intallation might really mess things up.