Can you catch hsv-1 from sharing a sandwhich with someone who has it but had no visble signs of an outbreak?

Very very unlikely: The answer is "no", but because real life can hold surprises, the answer is "very very unlikely". People who have gotten herpes 1 or herpes 2 will sometimes shed virus while having no symptoms. They are contagious during the shedding, but they can't tell when they are shedding. They are more contagious during an outbreak, because there are a lot more viruses there during an outbreak.