UA Intercept no invocation.proceed() not stopping submission

[rrawson]

Sprinkled with trace code in this to validate flow. Even if you don't return invocation.proceed() the submit proceeds anyway. 

Identity Manager Roles Based Provisioning Module Version 4.6.2.1
Build Revision 45048

form.interceptAction("SubmitAction", "before", function () {
form.alert("Verifying Submission");
var fieldScope = form.getAllValues("SERrequired")[0];

field.fireEvent("selectAll")
var errors = false;

if (!mandatoryMPI()) {
field.fireEvent("showError","epicSERIdentityTypes");
form.alert("epicSERIdentityTypes");
errors = true;
} else {
visine("epicSERIdentityTypes");
}

for (var i=0; i < dropdowns.length; i++) {
if ((fieldScope.indexOf(dropdowns[i]) != -1) && (form.getValue(dropdowns[i]) == "")) {
field.fireEvent("showError",dropdowns[i]);
form.alert(dropdowns[i]);
errors = true;
} else {
visine(dropdowns[i]);
}
}

if (!errors) {
form.alert("returning invocation.proceed()");
var result = invocation.proceed();
return result;
}
form.alert("end");
})