I'm about 2 1/2 months to late on this, but better late than never. This is my account of trying to enter Venezuela from Colombia at the Maicao border on 11/27/13 by way of bus.
I had been planning on going to Venezuela for months, but didn't know many people who had been so had little info. When I got to Colombia, I met a few travelers who had come from there and had a fantastic experience with no issues. I had also heard of people getting denied at the border but never actually met anyone first hand who had experienced it...so I was still skeptical. I looked all over the internet and checked the US site for visitors to Venezuela and saw no restrictions.
As such, I had to see for myself. In preparation, I went to the Western Union office in Santa Marta, Colombia to change pesos to US dollars. At that time the Venezuelan Bolivar (their currency) was suffering extreme inflation and was 60:1 to the US dollar on the black market (versus about 6:1 if you withdrew from an ATM there). I then went to the bus station to buy a ticket from Santa Marta to Maracaibo. The first bus company I spoke to actually had a printed sign that said for all citizens from the US, Canada & England, you need:
1. Proof of departure - printed copy of bus or plane ticket leaving Venezuela
2a. Documentation of Stay - printed copy of hotel reservations
OR 2b. Notarized Letter from a Venezuelan, explaining the relationship, length/place of stay and contact information of the host.
3. Passport...of course
The second bus company, Expreso Brasilia, had no such sign and said there were no problems, so I bought a ticket (Cost: 90,000 pesos or ~ $45). There were no other "tourists" on my bus, just Colombians & Venezuelans. We took off and headed for the border. As we got closer to Maicao, I laughed as I saw Colombians on the side of the road selling gasoline from Venezuela in jugs and 1 1/2 liter liquor bottles.
By the time we arrived at the border it was night time, about 7pm and I was nervous as hell. Everyone got off to get the exit stamp from Colombia and the driver told us that we need to walk to the Venezuelan side for immigration and he would meet us there. When I got to the window for my exit stamp, the official informed me that Venezuela has been denying many travelers at the border without proper paperwork and, if I don't get in, to come back there. All I had was a copy of a hotel reservation for 1 night so crossed my fingers.
I then walked to the Venezuelan side. Mind you, at this moment, I had $700 cash in my shoe and the electricity was out in Venezuela so it was dark. I was told by several people that this border is not the safest place to be & even met an Italian guy who had money taken from him by the Venzuelan police. I waited my turn in line as the immigration officer handled everything by candlelight. When I got to the window and gave him my passport, he flipped through, then pointed to a similar sign (as the one I saw in the bus station with the requirements listed above) and shook his finger, denying my entry. I gave him the copy of my hotel reservation, then he got up to go get another official. The second official looked at my passport and hotel reservation and also informed me I did not have the entry requirements.
I went back to my bus and told the bus driver, who then walked with me back to the immigration office to speak with the official. He came out of the office with no luck, saying he could not take me any further and I would have to stay in Colombia. I got my bags off the bus and the driver called some Colombian guy who walked me to a hotel across from the Colombian immigration office. I went back to have my Colombian exit stamp revoked, ate some dinner, drank a beer and watched "The Girl with the Dragon Tattoo" on TV in my room.
The next morning I took a moto taxi to Maicao and got a bus back to Santa Marta (for only 30,000 pesos)
I'm not surprised that I was denied entry into Venezuela but am still bummed because I really wanted to experience it. If you go, just have the proper paperwork and you should be fine. I guess I could have tried bribing the immigration official on the Venezuelan side, but didn't. If you want to be really adventurous, I met a guy from Morocco (while I was in Mica, Colombia) who had snuck into Venezuela because he had lost his passport. He spent a few weeks there and loved it.
Lastly, if you're wondering where to get Venezuelan Bolivars on the black market, there were money changers literally at the border offering the going rate. I had bought some bolivars from another traveler and exchanged them back into pesos at the going black market rate. You can also exchange US dollars for bolivars at some hostels or just meet some trustworthy locals and exchange with them.