Nobody is going to do silly things with him around...
semi-colons are for that purpose alone. You wouldn't dare use them...
You cannot use semi-colon here because semi-colons are used to split two parts of the sentence that are not related to one another.
Need to use colon because colon is a substitute of a word "because".
I don't agree; a semi-colon is like a comma + a conjunction.
A semi-colon is used to split sentences and create lists. A colon is correct, although a dash (or hyphen) is probably acceptable in modern standards.
A semi colon is correct. Separating the two clauses by a comma is a mistake called "comma splice".