Since his early "Project for Extraterrestrials" series, which used large overhead footprints to symbolize extraterrestrials 'movements in the sky above earth, Cai's explosion events have caused concern: What if the burning remnants of fireworks set off in a city caused a fire after descending?
起自早年「外星人」系列、象徵外星人行走地球上空的大腳印，在創作過程中一直備受質疑，因為煙火在城中一路施放，萬一爆破的碎屑落地後引發大火，那可怎麼辦？