Custom question: different default values for different environments?

[Kai Großjohann]

There is a defcustom tramp-methods which is a long (nested) list.  Its
default value contains "rsh" on most systems, but "remsh" on some
systems.

Now if people use Customize to change the variable, then ~/.emacs
will contain rsh or remsh.

Now if these people use the same ~/.emacs on another system, the
variable might contain the wrong entry for that system.

How to deal with this situation?

I'm guessing that the right strategy is not to deal with it at all,
because other variables in Emacs have the same problem, and adding
workarounds for such things just doesn't make sense.

(For example, load-path contains the Emacs version, so after
upgrading Emacs the value saved by Custom will be bad.)

Opinions?
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