I'll do a two week trip from Europe to Toronto and will fly back from New York. I plan to enter the US at Niagara Falls using a Greyhound bus (or Amtrak train alternatively). I meet all requirements for the Visa Waiver Program and had no problems entering the US a couple of years ago (under ESTA by air). However on the homepage of my American consulate, it says:
To qualify for the VWP, travelers from participating countries must:
If arriving by a land border, have proof of financial solvency and a domicile abroad;
What exactly does this mean? How do I have to prove that. Is there anything I can prepare beforehand and which documents/forms are needed besides my passport?