In some workflows, particularly the one in one of the important POCs today, unconditional application of the checksum test prevents replay from being used, even though the transaction logic does not in any way merit it.
The off-the-top proposal is to allow me to blacklist a bunch of tables and standard functions. MaxScale would skip the checksum if running into a SELECT from any one of these tables. It should be limited to selects without joins.
For the POC, a lot less is enough. Skip checksum test on SELECT LAST_INSERT_ID.