Some electrical workers use the terms ghost voltage and/or phantom voltage but these do not seem proper terms for anything to do with voltages in cables or on metallic items such as double insulated appliances. The correct terms that should be used are inductive, capacitive or leakage through a high impedance path voltages.
These voltages are typically non-lethal and are measurable. The amount of voltage measured will depend on the measuring device e.g. a proximity tester without any resolution of measurement will simply beep and flash.
A high-impedance multimeter on the voltage range, with an internal resistance/impedance of 10 MΩ, will accurately measure what may appear to be a dangerous voltage, since quality multimeters are designed to measure voltage precisely. It is quite feasible to measure 230 volts that is non-lethal using a high impedance multimeter on the voltage range.
To determine if a voltage is inductive, capacitive, leakage through a high impedance path voltages or lethal, plug a filter, designed to AS IEC 60990, into the multimeter terminals. This filter basically mimics the human body to allow the user to determine how much current would flow through the human body at approximately 2,000 Ω for d.c. and 50 Hz voltages. Place the meter on the voltage range to take the measurement and then calculate the touch current and touch voltage as follows:

Touch Current = meter reading/500 (in mA)
Touch Voltage = meter reading x 4 (in volts)
It is important to understand the levels of touch current that cause issues with the human body to understand the relevance of readings taken as above:
- The threshold of reaction is 0.5 mA.
- The threshold of let-go for an adult male is 10 mA.
- The threshold of ventricular fibrillation (rule of thumb) is 30 mA.
Inductive, capacitive and leakage through a high impedance path readings in typical residential and commercial premises will generally be non-lethal but the above methodology proves or disproves this.
The low impedance range on multimeters do NOT mimic the human body and are of little use in determining likely touch currents and touch voltages. Their impedance/resistance typically varies from 3,000 Ω at zero voltage to around 60,000 Ω at 230 volts.
In summary, the terms, ghost, phantom or stray voltages should not really be applied by electrical workers. The correct terminology is to use inductive, capacitive or leakage through a high impedance path voltages. These voltages are measurable to determine how dangerous these might be using a filter designed to AS IEC 60990.