I have sent several packages to Santo Domingo. None have been opened according to the receipient. The key is to be honest in declaring contents on the custom form. Or at least be in line with what that package should weigh.
Some tips: Do not declare that you are shipping a dress, when the package weighs 10 lbs. and you are really sending a box full of telephones. Common sense would cause the inspectors to be suspicious, based on the awkward package weight, resulting in your package being opened.
Another tip: Don't declare that you sending something stable, like a handbag, when you are actually shipping a contraption that has moving parts and rattles loudly. Again, Customs will know that a purse or handbag doesn't rattle like a box full of marbles. This type of blunder arouses suspicion again and will result in the package getting inspected.
Size and proportion: Don't declare you are sending a dozen baseballs and ship it in a box big enough to send a TV. Even if you may have the weigh in proportion, a box or package that is 10 times the size needed for what you are declaring will arouse Custom inspector suspicion.
I hope this has helped.