IIRC you can edit the exported html (I think) to disallow syskeys. I recall Ashley responding to a thread about a similar issue, but regarding the spacebar, which also causes the page to scroll.
But yeah, I'd agree that this is something that would be nice to be able to include when you're exporting, along with some simple tools to let you customise your game page or whatever (mostly because I'm not good with CSS, at all).