Sec 3.4.2 tries to explain aliases and mailing lists. While I think there is a useful distinction between lists that rewrite the bounce address and aliases that don't, most of the rest of the section seems out of date. Nobody I know cares about "exploders" any more; if there are 10 people at site x, as often as not one sends ten copies of the message and nobody cares.
The bit in 3.4.2 about not changing the header I think really means not rewriting existing headers, i.e., don't treat it as submission. Adding more headers seems harmless.
Sec 3.4.2 tries to explain aliases and mailing lists. While I think there is a useful distinction between lists that rewrite the bounce address and aliases that don't, most of the rest of the section seems out of date. Nobody I know cares about "exploders" any more; if there are 10 people at site x, as often as not one sends ten copies of the message and nobody cares.
The bit in 3.4.2 about not changing the header I think really means not rewriting existing headers, i.e., don't treat it as submission. Adding more headers seems harmless.