If members of the German Bundestag change their parliamentary group...

1. they are no longer allowed to participate in parliamentary sessions.
2. the government may lose its majority. ✓
3. the Federal President must first give their consent.
4. the voters of these members are allowed to vote again.

Because the government needs a majority to pass laws, members switching groups can change the balance of power. This is why stability in coalition agreements is so important in German politics!