> In any case, the only minimum requirement would be that (t ...) would validly return a "useless" value without any side-effects and cannot be redefined.
Well, you have the last part of your wish. t is the symbol representing true in Arc and cannot be redefined. ;-)
I know, hence the ;-). All I was saying is that you have to choose a symbol different from t, as you will not be able to define a meaning for (t ...), let alone redefine it.