If you see one or even no alarms when you create and save your event in Informant, then after it syncs you see an alarm has been added, this is coming from your google calendar settings.

Google has the option to add an alarm to new events.  So when you create an event in Informant and it syncs to google, it will add the alarm then since it sees that it is a new event.  You can go into your google calendar settings online and turn off or adjust that alarm as you need to.