This analogy to computer protocols is interesting, but it reminds me of
the maxim commonly employed by engineers who must interface to these
protocols: be permissive in what you accept and careful in what you send.
For example, from the S/MIME interoperability profiles guide,
"Throughout this paper, there are separate requirements and
recommendations made for the handling of incoming messages versus the
creation of outgoing messages. In general, the often quoted,
proverbial strategy is to 'be liberal in what you receive and
conservative in what you send'. Most of the requirements are placed
on the handling of incoming messages while the recommendations are
mostly on the creation of outgoing messages. To rewrite the proverb
somewhat, 'you are required to be liberal in what you receive and it
is recommended that you be conservative in what you send.'"
This is standard engineering practice in designing for maximum inter-
operability. (And even with this, interoperability is a chancy thing
and is seldom achieved without actual interoperation testing.)
Applying this advice to personal relations, it would be consistent with
the first part of your advice about making your acceptance of input
more robust. But rather than seeing this as "instead of" being careful
about what you say, it suggests that the two strategies are complementary.