In one aspect, a method includes (i) accessing broadcast-schedule data associated with a channel; (ii) using the accessed broadcast-schedule data to identify an upcoming content-modification opportunity on the channel; and (iii) responsive to identifying the upcoming content-modification opportunity on the channel, performing an action to facilitate performing a content-modification operation related to the identified upcoming content-modification opportunity on the channel, wherein performing the action comprises causing in-band message data to be inserted into at least a portion of a content segment that is being transmitted by a content-distribution system on the channel.