I do not want my systems to play sound, ever (POST beeps would be ok). Is there a way to do this in the system, preferrably something that could be set at boot or login? Or if necessary, compiling a custom kernel, though something I could use when working on other people's machines would be most useful.
This question was provoked by comments here https://ux.stackexchange.com/questions/104893/what-is-the-significance-of-the-start-up-sound-of-a-system from a person who thinks my usual method of just removing the speakers is excessive. But I can't think of another way to do it, or find one with a Google search. Setting volume to zero doesn't work, at least in my experience, because some programs/web sites seem to be able to override that.
Edit to add some info in response to comments:
I have several systems of my own. The ones I use most are Lenovo T61 Thinkpads, so I don't really know what they have for sound internally. The couple of tower boxes are home-brew (Gigabyte motherboards) and I'm pretty sure they don't have sound cards, as I use them almost exclusively as compute & storage servers - and almost always access them via ssh.
The OS is various iterations of OpenSuSE, from (I think)13.1 to a recent 42.?. I use FVWM window manager.