It's still an option now, however it looks like they too will lose banking access in China soon.
>The impact of the Chinese ruling on LakeBTC is limited. The only major change is that our services to all Chinese citizens will be suspended. LakeBTC is a legitimate business which follows applicable laws and regulations.
The type of arbitrage you described has been going on for years, especially for ETH where 20% price differential isn't uncommon at all. The difficult part, however, is getting money in and out of China without raising suspicion. By the time you have paid off all middleman the margin isn't that great anymore.
>The impact of the Chinese ruling on LakeBTC is limited. The only major change is that our services to all Chinese citizens will be suspended. LakeBTC is a legitimate business which follows applicable laws and regulations.
Source: https://www.lakebtc.com/p/9352
The type of arbitrage you described has been going on for years, especially for ETH where 20% price differential isn't uncommon at all. The difficult part, however, is getting money in and out of China without raising suspicion. By the time you have paid off all middleman the margin isn't that great anymore.