Hello Gcl581,
Fido Roam charges will only incur if your phone uses services -- make or receive a call, send a text message or use data abroad. It should be mentioned that while receiving SMS would not incur the roaming charge, any data contained within MMS (incoming or outgoing) would be considered roaming data and charged accordingly. You should note that MMS are not solely restricted to pictures or video messages. Messages with subject headers or group messages etc are also considered MMS. It should further be noted that iMessages and RCS messages are sent (and received) as data and not as text messages (SMS). Even if the text message received is SMS, if your device is configured to provide Delivery and/or Read receipts, those would be sent as SMS or data and considered roaming usage.
Unanswered incoming calls and having them go to voicemail should also not incur roaming charges (see here and here). However, it should be noted that checking your voicemail would be considered roaming as one must call the voicemail service. In addition, it should also be mentioned that the Voicemail-to-text feature notifications would be sent as MMS (roaming data). Similarly, I believe iPhone's Visual Voicemail would use data (roaming, if abroad).
Hope this helps 😀
Cheers
