So you can't have any plants at all but if you have more than five you will always be persecuted. Perhaps the renter that got kicked out had violated some kind of agreement. It was social housing though, which is really common in The Netherlands, so I imagine a lot of people are facing the same problem.

Yeah, but why would the police ever see your plants at all?

Also keep in mind that the police in the Netherlands is not as trigger happy as American police by a long shot. You're not getting swatted for having a few plants because our police is not militarized at all, we have a separate branch of LE that does riots and SWAT-like tasks and they're mostly used for large drug operations and soccer riots.

AFAIK as long as you're not using high-powered lighting (and not the modern LEDs or sunlight), tapping the neighbors' electricity and therewith creating a fire hazard you're fine.

Plantations are usually found either by the electricity company or because a helicopter with IR vision (or regylar vision on a snowy day) happens to find a house with an unusually hot roof.