I specified that the perp is both facing me and in my home (as opposed to my possibly 1000 acre lot - I wish). This scenario is legitimate self defense in all 50 states (unlike some states in Europe)
The owners, the police, the prosecutor and the jury would be far more interested in the breaking and entry charge than the $1000.
In fact, in every state of the Union, if you're facing me whilst committing the act of trespassing inside my home, I can legally punch a hole through your torso with a 9mm.
You're comparing an island with millions of people to Andorra?
Except for Luxembourg a few hundred guys could besiege all of the states listed above. Ten thousand would suffice for Luxembourg. As it stands no one is really sure if China - with one of the the world's largest armed forced - could successfully invade Taiwan.
Lets add San Marino, Monaco and the Vatican for good measure.
All those states have very specific historical reasons why they dodged unification with their surrounding countries. The most surreal being Monaco's sovereignty saved by Grace Kelly's fame as an actress moving American public opinion to pressure France not to swallow it.
Also, note, that all the towns you listed are (historically) worthless border towns wedged between titans who would violently oppose their neighbor swallowing them. Sure, now those microstates are rich, but historically they were worthless and not worth war with a powerful neighbor to take over.