Your comment is mis-leading. If you have some hardware fail and you contact Meraki support, and it has a current licence, the kit ships "next business day". You do not require Meraki Now for this.
Meraki Now lets you buy additional response times like 8x5x4. However it is very expensive, and it is usually cheaper to buy a cold spare.
"Unless you have purchased Meraki Now, advance replacement orders will ship within 1 business day on a best case effort basis."
The 5 day RMA process you are referring to relates to non-failure RMAs.