The custom code condition 'check-in is in ... days ' uses units of days as a whole, and does not break them down into hours.

This means that a condition of 'check-in is in less than 2 days' is met only when the event happened 1 day or less prior to check-in. We do not treat it as less than 48 hours. Instead, it functions as "less than 24 hours".

If the check-in were on Nov 3rd, at 1PM, the custom code would not be populated if the message is sent anytime on Nov 1st or earlier. It would not be populated if sent on Nov 1st 5 PM, which is technically less than 48 hours from the check-in. For the custom code to be sent on Nov 1st, you would need the condition 'check-in is in exactly ... days', or 'check-in is in less than 3 days'.

This hypothetical message would only include the custom code with 'check-in is in less than 2 days' if the message was sent on the Nov 2nd, anytime past midnight.