The scenario is:
you are creating a slave transaction and you need to use transactionid value for logs and other things. You know what you are doing and you write the transaction knowing that it uses transactionid and it will need persistence "always".
Then you give this transaction to another software developer and you explain the interface of the transaction. He calls your transaction in his software...and your transaction doesn't work for inherit/onError/Always parameter.
In my opinion you should know everything of your transaction (for example the requirement of persistence), but nothing of the transaction done from other developers (just I/O description). The developer of slave transaction should configure it in secure way (he should fixes persistence of his transactions, if it is necessary a specific value).
But, if it is not possible, I will explain to everybody the persistence requirement. And I will hope that nobody will forget this important parameter...
Best regards
Fabio
