This is not uncommon. Most of the other chain English mills do this too, especially for their highly-profitable Summer and Winter camps. They will tell you it's OK, but they are lying to you in order to maintain their margins...at your risk.

Problems at EF only begin with the visa. There do seem to be a couple of decent EF schools in China, but complaints about most of them are prevalent across the EFL internet.

The chains got to be chains by being efficient and profitable. Teacher treatment is pretty much coincidental to this, as is claiming to be "American owned" or "UK-based" or what have you. There is currently NO chain school in China I would recommend to anyone with the possible exception of Wall Street.