Uhhhhh, yeah. First of all, there are some countries (i.e., Canada) that are unlikely to let you in while you are on probation for a crime. Second, a warrant will be issued for your arrest. If you are ever stopped anywhere for any reason (i.e., jaywalking, speeding, etc.), then you risk the warrant coming to light. If the warrant comes to light, you will be taken into custody and may end up sitting for months while WI decides whether it will extradite you. If WI extradites you, you will be sentenced on your probation revocation, which can be up to the maxium sentence for the crime that put you on probation. If you are not extradited, you are released, and possibly doomed to repeat the procedure next time, as the warrant will likely not just go away after that....
Granted another country is not likely to know about the WI warrant, but why take the risk?
Well let me start off as saying, You should absolutely not do that.
That being said, some countries will demand a VISA before you are allowed to enter, or run a criminal background check upon you before allowing your admission to the country (meaning before you get through customs). If that happens, you will be sent back to the US, and there may likely be a law enforcement escort waiting to take you to the local jail. Only to be taken to an extradition hearing, and a long bus ride back to the State of Wisconsin.
For those that do not, there may well be extradition treaties that will allow you to be returned to the United States. Within the past few years there was an individual accused of sexual assault of a child, he ran to Costa Rica and set up as a realtor there. About 6 or 8 years later they found him, and extradited him back to the US, and then prosecuted him. They brought up his flight from authority as evidence of guild and he received a lengthy prison sentence. So yes, in that case there clearly was consequences. Again, I would strongly recommend against such actions.