It depends how you use the tool, if you do research via using tools, other users won’t be able to see your data, if you monitor your websites via tools, in that case, other users might see your data.
No, although we try our best to provide maximum uptime as it’s our business, however, sometime tool provider block accounts, sometime limit exceeds and sometime due to an update from provider tools might not work properly, although we try our best to provide maximum uptime to our users.
For most of the tools we have nearly 99.9% uptime, for very few tools we have nearly 80% uptime.