A couple months ago we had yet another example of "that will never happen" caused by people ignoring upper bounds. Developers never saw any problem, of course; and who cares about all the users who had compiles explode with unexpected errors? I think it took less than two weeks after someone patched up the most visibly affected packages before developers were shouting to remove upper bounds from the PVP again, because the affected users are just users and apparently not important enough to consider when setting versioning policy.
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