[lolinder]

Most of these questions have easy answers in the implementations already out there:

* Set a maximum size on a sign. You can have a sign in front of your shop or on your car as long as it isn't larger than a well-defined square footage.

* If no one paid to have skittles mentioned, it's not advertising.

* Accepting and giving gifts in professional contexts is already known to be fraught, an anti-advertising law wouldn't significantly alter that.

* If the competitor paid you to share the negative experience or paid for the airtime/venue in which your shared it, it's advertising, otherwise it's not.