You have a dagger (†) warning for when the margin of error is 10% of the estimate, but the more appropriate way to do this is to use the coefficient of variation (see link below) to assess the MoE. It's also called the "relative standard error" and is a way to assess whether the margin of error is "too high" for the estimate to be of any use. I would recommend showing the dagger warning when the coefficient of variation exceeds 30%. For broader audience communication purposes, you could say something like, "The margin of error for this estimate is high and the estimate may be unreliable. Use caution." And then maybe link to more information about the CV.

We use this approach at the City of Portland when we are using small geography estimates. If the CV is over 30%, we do not rely on the data as a decision point.

http://help.arcgis.com/en/businessanalyst/apis/rest/reference/ACSVariables.html