I have both browsers icons next to each other and sometimes I launch the other by mistake. For normal browsing I only spot the difference due to various pages having different logins ie from my wife or not being logged in.
If somebody is able to use internet (god forbid even do some payments on it) then I am pretty sure they could understand the concept of another, very similar app with same behavior. Sometimes new releases change UI at least as much as those browsers differ between each other.