Only you can answer that question by looking at your account and seeing what plan you have.
If you are being told you are over your data limit, it is unlikely you are on an unlimited data plan and will be charged an overage fee for further data usage unless you have a plan which also includes safety mode and you have it activated.
Logging into your account and seeing what is included with your plan would be a good first step to take to finding out if you have unlimited data.
They can also get the notification if they go over their high speed hotspot data allowance with an unlimited data plan.
I'm most definitely NOT a VZW employee. If a post answered your question, please mark it as the answer.
I know the importance of having the proper access to the data on your phone with the right plan, kimscaggs. Thank you to the community for the great replies! Here is a link to log into your online account and review your current plan: http://spr.ly/6606EtkKG YaleK_VZW