It's incredibly straightforward to prevent zoombombing, you simply set a password on your room. I would be surprised if Zoom hadn't made this the default by Monday.

Prior to the age of 'zoombombing', frictionless entry to every meeting was a nice feature, and meeting IDs are difficult enough to guess (11 digit number) that entry of uninvited guests basically never happened.

Now that everyone has so much spare time, the worst elements of society are using it to try to harass children. I guess the tragedy of the commons kicks into full swing and we must have passwords going forward.