It's my understanding that the only way to use a private Fusion Table with the Maps API is if you're using the Business version of the API. Only public and unlisted tables can be used normally. I would really like to realize the performance benefits of Fusion Tables but am not interested in paying for a business license.
My question is this: How secure could an unlisted table be? The data I'll be displaying is sensitive, but not critical. It is unlikely to be sought out specifically, or scraped by a bot. (no addresses, names of people, phone numbers, etc).
If Fusion Tables really won't be an option for me and my sensitive data, with MySQL at what point would I start to see serious degradation based on the number of markers in an average browser? I estimate the maximum number of points in the table to be somewhere around 1000-2000.