At least in Germany, and I imagine it would be similar in the Netherlands, it would be the parliament's president because political symbols on clothing are not allowed.

The speaker of the house asked her, but only when urged to by another member of parliament who reminded him that earlier this year, another member was asked to change the T-shirt he was wearing with a foetus on it during a debate about abortion. The rule is that the appearance of the parliament should be neutral.

By the way, because she was asked to change her clothes, the moment was aired in all talk shows that evening, with an explanation of the watermelon blouse she wore later (and which the speaker suggested she wore instead by the way), so this incident only helped to get her message out there.