Hello! I need your opinions, please.

So Southwest Airlines has periodic sales, where flights get pretty cheap. They had a super-sale a few months ago so I sent an email to our out of town guests (bcc'ed) letting them know about the sale. Save the dates had gone out, but not invitations, and I even said something along the lines of "no need to decide yes or no yet, but if you had already decided yes, here's this airfare sale that you could take advantage of." I made sure to only send it to guests that live in cities with SW airports, and there are three airports within 30 minutes of where our wedding is that Southwest flies to.
Anyway, so to my question. I sent this email I think back in April, and Southwest is having another sale now. My fiance wants me to email everyone again, but I feel like if I do we might be pushing people to RSVP. Our invites will go out later this month, and our wedding is last weekend in September.
What do you think? My attitude is, we already told them once, they should be able to figure it out from here. But, my fiance really wants to be able to help them save money if at all possible, and sees no problem with a 2nd reminder.
Thanks!