Thanks for your response and the opportunity to chat designwise.
This is definitely not the intended behavior. Do you happen to know what version of the plugin you were using?
Version 1.x did write some code to the DOM, but it was a dynamic insertion and in no way should hang around. This code was not written to the database either, it is inserted upon page load. The only information the plugin (v1.x or 2.x) inserts into the database is the plugin settings and your Roost appkey.
Version 2 of the plugin does not write this code block, rather handles everything from a single JavaScript include where your settings are controlled from the admin panel.
Do you happen to use a CDN or some other optimization on your site? The only way I can figure this would make sense is if a CDN or your browser cached your page, which would act as if the code for the Roost plugin had actually been inserted into the database or page view.
Regardless, this is not our intention nor should it work this way.
May we discuss off this thread a 15 minute time slot where we could screen share and review your site? I will be more than happy to get your rolling with Roost (with it behaving properly) or help you fully remove this from your site.