Comment 2 for bug 1335175

The rule that the first tag with options wins (and also overrides global options) is arbitrary, there to provide some predictability, but if we switch to combining tags we then need to make an arbitrary choice of which order in which to combine them (assuming it matters).

Another problem arises if two or more tags have conflicting kernel options. You've got to be strict then to avoid assigning multiple of these tags to a single node. Only using the options from a single tag avoids this problem.

A concept like radio-groups for tags might help, where a subset of tags can be said to be in a group, and only one of the group can be selected at a time. These could be used for conflicting kernel options. However, how would these play with auto tags? Also, we kind of have these already with physical zones.

That's not to say that we shouldn't combine options, but we do need to give it more thought before we do because it's a subtle problem.