That works partly as if i submit with out selecting or adding content I get the correct warning for both form elements but if I tick one of the check boxs excluding the first only and I dont add the required text to the field I get the same warning about both missing. It appears that only the first box being ticked will prevent this from happening.
However by selecting any check box and adding the required text the form submits as it should so while the validation does work it could cause confusion if the final user selects the options oulined above.
I am not sure there is a workaround for this.