Yes, I've actually thought long and hard about this. I feel it is OK if it's done with filters. You will not be allowed to accept any and every invite. Only accounts that already have several exchanges active will be allowed to auto accept. Only so many auto accepts will be allowed per day. Only accounts with X amount of SP can auto accept. Etc. (more rules can be added as necessary).

Every invite creation requires the completion of a captcha. This coupled with the fact that someone is unlikely to send an invite to a spammer, the likely-hood of this being used for spam is very low. If a spammer had 100 sock puppet accounts and wanted them all to upvote each other SteemAX would be a very poor way to do it. That's a lot of captchas to complete and a lot of logging into Steem Connect! And wow, they can only do it 5 times a day. It would take them days and weeks to do it this way. And what's the other fear? That spammers will get together and create exchanges with each other? Still unlikely for the same reasons.