This isnt a problem with Webflow. The spammers do not even go on your site. They use robots to make you want to click on the link [provided in Analytics] of where your false traffic is coming for. They would then have the ability to collect a percentage of money if you were being payed by Google. I do not use Google Analytics anymore [for this reason] but you can disable information for these “sites” by going to a special section in analytics and blocking them off.
You would have to do research on how to do this since I have already long forgotten how to do this technique. The negative impact though is that then new robots can come in and you would have to type in new robots [names] to block. Pretty much it goes around in a circle.
robots > robots blocked > new robots > robots blocked > newer roots > you give up and get a better service. (added that one for fun) 
Hope this helps. 