Is there a way to determine whether an event will be provided live?

You can check it via rest calls to /sport_events/{id}/fixture or /sport_events/{id}/summary. If the sport_event_status element contains the liveodds="not_available" attribute, then the match is prematch-only. Be aware that this flag can be changed if the coverage for the match changes – in such cases, you should receive a fixture change message with the change_type="5" attribute from the feed informing you about it.