The parent said "droplet" so I assume Digital Ocean. Unless you've installed the host yourself, from scratch, you can't be sure the option hasn't been changed.

Makes me think that your setting is a default and his was set by Digital Ocean.

No, I have another Ubuntu 16.04 machine at home - same kernel version, same settings. He must have installed kernel 4.11 manually , because linux-image-generic currently pulls kernel 4.4.0-101-generic on 16.04; settings depend on kernel version.

Yes, I find it interesting that DO would change random kernel flags.

I suspect settings actually depend on kernel version: 4.4 -> 'always', 4.11 -> 'madvise'

Perhaps there are issues with 'madvise' in kernels prior to 4.11, so they chose 'always' rather than 'never'.