Will multimeter show a voltage in an electric field?
A multi-meter can show a reading when moved through an electric field, however when its stationary, it rapidly dissipates the charge over its generally 10 megaohm input resistance, equally any charge that is developed on the probe is largely attenuated by the meters input capacitance (10's to 100's of pF)

The meter's input capacitance is also why you can measure frequencies on some meters with no ground connected. However with DC voltage the other probe quickly charges up to the DC voltage via the 10M resistance and shows 0 after the initial spike.