Mime type detection in URIInputParameter.check

On lines 103-106  there is a precheck that issues a head request to the target url.   In some instances, this check will return a different mime type than what the ultimate get request would return.   A case that illustrates is a Unicorn General Conformance check to https://www.verizonwireless.com/smartphones/ <https://www.verizonwireless.com/smartphones/>, a head request here returns application/json as the mime type which in effect cancels the test ( as that is not a valid mime type for any of the observers).    I suspect that it can simply use GET instead of HEAD but don’t know if this is exactly a bug or not.   Is this a bug or something that could be addressed?

Thanks

Jeremy