Algos aren't smart. Thy automate human reasoning to the extent logically possible. If as a human you don't know how to detect a spoofed bid, then how do you make algorithm "smarter" than yourself?
If the algos aren't smart, then you may wish to rethink trading real money with them.
The orderbook imbalance signal is a strong signal, but its not the only one...
(Full disclaimer: I worked as an algo quant at a large bank for 5 years. During which time I was constantly hounded by Compliance over supposed "spoofing", which we never did.)
