Again, incorrect.

RBF is optional for sender (opt-in), but not optional for receiver. Educate youself, granny:
1. https://www.reddit.com/r/btc/comments/42m4po/its_a_sad_day_when_core_devs_appear_to_understand/
2. especially: https://www.reddit.com/r/btc/comments/42lhe7/usability_nightmare_rbf_is_sort_of_like_writing_a/
3. https://www.reddit.com/r/Bitcoin/comments/3zju81/rbf_optin_a_man_walk_in_a_bar_order_a_coffe_drink/

In short: You can choose whether to send RBF, you can choose whether to mine RBF, but you cannot choose whether you receive it or not.
"RBF is sort of like writing a paper check, but filling in the recipient's name and the amount in pencil so you can erase it later and change it." - /u/rowdy_beaver (self.btc).

RBF could have the potential to completely destroy 0-conf transactions widely & successfully used today.

Bitcoin Core is a disaster waiting to happen.