Note that LCO product will in general not crack significantly under every catalytic system/operating conditions.
Concerning the purpose of the LCO quench, it is indeed for process optimization (even though there might be, here and there, an FCCU under severe mechanical constraint utilizing this feature to make sure a design temperature or limitation of some kind is not exceeded).
The quick cooldown of the effluent will allow limiting the prevalence of the thermal cracking in an area where there is substantially less catalyst particles available for the hydrocarbons to undergo catalytic cracking.
As such, there is no major risk in trying to operate without the quench.
Note though that, beyond the expected shift in yield structure which could result in a saturation of the columns processing lighter ends or rotating machines, this will normally result in a significant increase in gasoline diolefins concentration.
So, as usual, some precautions must be taken to ensure you will not mess with downstream hydroprocessing, if any, of with you mogas pool quality.