Browser-sniffing alternative for bugs/misbehaviors (NOT lack of features)

Ok we all know that browser sniffing is bad. I'm not looking to rehash the entire debate here, and SO isn't the right forum for that anyway. I'm looking for a solution to a problem that the proposed alternative of feature-detection doesn't seem to address.

In my particular case it was triggered by code like the following:

<form name="something" method="POST">
     <input name="input1"><input name="input2"> <!-- etc -->
     <input id="mysubmit" type="submit" value="Submit me">
</form>

<!-- during jquery initialization -->

$('#mysubmit').click(function() {
   sendAjaxRequestInsteadOfRealForm($('#input1').val(), $('#input2').val());
   return false;
});

Now, I know that the real answer here is "don't use input type="submit" with jQuery bindings" (other than submit, I suppose). But this code worked as expected on all of our "officially" supported browsers, and it was only when we had a user who happened to try the site in IE 7 that this became a problem (namely, it bypassed the binding and submitted the form the old-fashioned way).

We don't test on IE 7. So we try to use browser detection on our front page and warn users whose User-Agent indicates their browser is unsupported. I don't like doing this, but I'm unclear on what the alternative is. I can't think of a feature-detection strategy that would detect "allows click bindings on submit buttons to replace actual submission". What's the best approach h开发者_如何学JAVAere?

EDIT for clarification: I'm not asking for alternatives to the code above. I know what they are. I'm asking how I should detect the above code as problematic so that it would not have reached production, without having to actually test it in IE 7.

Hijack the default button event?

$('#mysubmit').click(function() {
    event.preventDefault();  // don't let the click event happen
    sendAjaxRequestInsteadOfRealForm($('#input1').val(), $('#input2').val());
    return false;
});