You could get caught at any point. That said I know people who have ordered literally hundreds of packages over half a dozen years without a single interception. I think if you are importing it is more worrying than if you order domestically. In my experience, usually it is safe to say that if you import packages, you will probably get caught at some point. It probably wont be the first time, it probably wont be the twentieth time, but usually it seems people who continue to import packages eventually have one of them intercepted, and it happens a lot quicker than people who stick to domestic packages.  If you want some statistics fresh out of my ass, I would say maybe the odds of interception for a well packaged not massively sized international package are maybe 1:100, and for domestic maybe 1:1,000. This is a gross over simplification and I don't claim it to be actually true, but I think that is a way to look at the risk difference and a very rough estimate of how likely you are to have a package seized in either scenario.