Actually there are a few biblical examples where they didn't repent but went to heaven anyways or were forgiven. One prime example is the thief on the cross. Another example is the woman that was a bad sinner that washed Jesus feet with her tears. And yet another example is the parable of the Tax Collector and Pharisee. The tax collector knew he was a sinner and asked for mercy and he went away justified. The Pharisee on the other hand liked pointing out that the Tax Collector was a sinner, he left less justified or not at all.
You sound like you follow a works based salvation. But that is not entirely biblical. And while it is wise not to sin, we should not be judgmental of others that do. That can ruin our salvation. And that is what Jesus teaches in the bible.
Surely the chap on the cross repented, otherwise Jesus wouldn't have said "Today you'll be with me in paradise', and likewise the woman who washed Jesus's feet was surely an act of repentance.
If you think unrepentant sinners go to heaven, I don't think so or it'd be a case of "oops there goes the neighbourhood and I wouldn't wanna go..:)
And what's a "works based salvation"? No doubt some hard workers think it'll guarantee them a free pass through the pearlies, but they just become sad workaholics.