When considering whether a control is appropriate for the
operation, the implementation is not only to consider whether the
control is attached to a message it was intended to be used
with, but whether the control is being used appropriately
in combination with other controls (of same or different
controlType).
When a server is faced with a sequence
of controls which are not appropriate for the operation,
the server may attempt, by ignoring any number of
non-critical controls (including controls whose criticality
field is to be ignored as discussed above), a sequence which
is appropriate for the operation.