Walked outside this morning and noticed the HVAC guy left his monitor hooked up to our unit after servicing the unit for freezing over 2 days ago. Is this concerning or normal?

Our 3 year old Raheem unit froze over during the cold snap here in NC. Local company came out and defrosted the unit and added refrigerant. I noticed this morning that the monitor and gas lines are still hooked into the system. The unit is working but I turned it off when I saw this. Can this damage my unit or is this some kind of data collection by the company? I am so confused. Thank you.