Stop in for a cup of coffee

OK you home owners. My wife wants an auxiliary drain tray for under our new frig we will get next week. I know they already have a built in tray by design but she want's extra protection you know, in case the icemaker line leaks. She thinks I can just order one and have it here. I think I need to see what the underside of the frig looks like. It might be close enough to the floor that one won't slide in. I don't know where she get's these crazy ideas.
Well in all our years with modern fridges we have never needed a back up auxiliary water tray? I would maybe verify you actually need one before enduring the frustration and cost of installing one?