I post about this all the time but I'll just do it again cause there's loads of misinfo on the topic, essentially however there's really minimal risk involved if you want to take out your restrictor and I'll explain why.

Firstly the restrictor doesn't actually have any confinements on what it can be, it can be anything from a washer in the carbs to literally a throttle pin to stop your bike revving all the way to the redline, essentially if it limits your bhp, it's a restrictor.

Secondly, the only way of checking your bhp is with a Dynamometer which most police forces/insurance companies either don't have access to or can't afford.

What this means is it's very very hard for police, even traffic cops to enforce. If you get pulled over at the side of the road they're really unlikely to want to dyno your bike to check its horsepower (unless you were acting like a complete dick and doing say 80 in a 30). They can't physically inspect it for its bhp, obviously, so there isn't really any options there.
I think they can request proof that the restrictors fitted if they wanted to be really petty, but then all you'd have to do is either fit one and get proof from whoevers fitted it, then take it back out again.

The same sorta implies to insurance companies and again they don't really have the time or money or even thinking ability to check the bikes bhp in the event of a claim, especially if it's not relevant to the claim. They're more likely to get it dyno'd if you're in a high speed crash, or if they're looking for an a way of not paying out, but even then it's not likely.

TLDR ; take it out, but don't be a wank