To be honest I haven't Micky. I personally haven't yet worked at any venues with CO2 alarms but am sure you are right that some do. That said, the dry ice sublimates at ground level and by the time it disperses into the general room's air the proportion would be negligible and not sufficient to trigger a CO2 alarm unless you were using a colossal amount in a very small room or the alarm was on the floor as demonstrated with the smoke one here. 10Kg is ample for 3-5 minutes' effect and I'd imagine you'd need several times that to cause any risk of activating one even in a small, enclosed room. Hope this helps.