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.)

One should seek to determine the theoretical price (i.e. "true" price) of an asset. If the spoof bid is above the theoretical price, then you hit it. The spoof bid is noise... find the signal and make the spoofers pay dearly.