Some physical hypotheses to explain the SLIder phenomenon

The hypothesis of a energy  wave produced by the human body

Whenever a charged particle is accelerated, it can produce a radio wave. The brain can produce electrical waves. However, they are very low intensities. It is reasonable to strongly doubt that celebratory brain waves can influence a lamp operating on voltages of 120 or 220 volts. This assumption is very unlikely.

The heart produces the most powerful current in our body. This current can generate a magnetic field that can be detected more than one meter away from a person. Again, the current produced by the human heart is unlikely to affect the operation of an electric street lamp. Moreover, the intensity of this field decreases with the square of the distance. A few meters away, the field is so weak that it is virtually undetectable. This hypothesis is also very unlikely.

Another possibility is that a person's heart beats between 60 and 100 times a minute. Electric current in America is 60 Hz. Street power lines produce much stronger electromagnetic fields. It may be possible that under certain circumstances there may be a coupling between the field of the human body and the field of the electrical street wires. Sort of like a transformer. The two fields would then enter into resonances. This spike in magnetic energy would be sufficient to affect the normal operation of the lamp.