Apple Pay Setup - $0 Transaction St. Louis, MO

I have been using Apple Pay for some time and really like it. It works with my debit card, which I also use the Card Valet app my bank offers to monitor card usage. Last week, while setting up my new Apple Watch I saw a $0 charge on Card Valet from St Louis MO. Not realizing it was part of the Apple Watch/Pay setup I called and had my card debit cancelled as didn't make any recent transactions nor have I ever been to MO.

Got my new debit card card a few days later and set it up in Card Valet for monitoring. I, in-fact, went a step further and set it to deny any online or mail/phone orders as I only use my debit card in person. Went to enroll the new card in Apple Pay and was unsuccessful. I then got a notification from Card Valet that a mail/phone order transaction was denied. I changed that setting to allow and to my surprise I saw another $0 from St Louis. I immediately felt foolish that I didn't realize what happened last time during my watch setup.

It would be nice to see some documentation that there will be a $0 pre-auth from Apple (St Louis) when you setup Apple Pay so others understand what is happening. Also, do all Apple Pay transactions go through as mail/phone order or is just the pre-auth? I want to continue to use Apple Pay, but don't want to leave that mail/phone order transaction type open if I don't need too.

Thanks.