I think that under normal weather conditions you''d be hard pressed to knock over a Cal 34, but then that really wasn'' the question. If you remember the Priority Order of Sailing you can avoid the situation:
First it is about the wind: how much, how steady, from where.
Second it is the boat: sail plan, stability and set of sails, mindful of the wind.
Third, it is the crew: number, experience, training, mindful of the boat and its needs in the wind at hand.
Fourthly, it is the passengers: their comfort and safety, but you cannot address this without the first three being considered.
When you go out, go down this list, adjusting each of the four to handle the situation ahead of it. You''ll be fine then.
enjoy the experience