there's an important difference between with and without a visa though: having a visa you're not supposed to be refused entry. It comes down to having been given entry permission by the respective country's MFA, which ought to have weighed in all the relevant factors available, e.g. also your entry history. Although an IO can technically refuse entry even to entrants with a visa, we must assume that they won't. Not having a visa means that whether or not you are good to enter is entirely determined by the IO, and that's where your history is then considered.
It's often advised to check with them, which you could, but you could also safe yourself the time. Any airline will say that you are required to have proof of onward travel if you plan to use visa exemption. It doesn't mean that you will actually get checked.