[PeterSL]

Reading section 263 of the Criminal Code would in itself suggest that, as RavYak says, "The way this law is written you only have to guard and warn."
However, The law in Canada is made of two parts: Legislation e.g. The Criminal Code, and Case Law. Both are primary sources for Canadian law.

Case law is made up of the written decisions of judges in court cases and tribunals. Case law comes from all levels of courts in Canada. Interpretation of legislation evolves over time from actual trials and appeals etc. i.e case law.

In this instance the case law suggests that if harm occurs as a result of making a hole in the ice at a place frequented by the public, then no matter what precautions were taken they were clearly not 'adequate' enough. The efforts of Todd and his mother to safeguard the hole might mitigate the liability but would likely not eliminate it. If you were CEO of the ACA would you then take a chance that all will be well and send out your staff to make holes in the ice? Would your staff be happy to take that risk?

The only solution I see is a change to the legislation. Hopefully the ACA will have some other solutions to report on Oct 17th, though I'm not optimistic. We may have to have an incident occur, a good lawyer, and a judge who values and applies the concept of 'due diligence'. Thereby, perhaps some case law can be established for reasonable as opposed to absolute responsibility regarding the lake aeration programs across Canada.