First things first I try to never offer advice I wasn't asked for (don't always succeed but ya know). Now if I am asked the easiest way that I've found to go about it is but stating what you seen with your animals. i.e. "Can you keep two ball pythons in one tank?" short answer is "yes you can people do it all the time, now there are some relative dangers to be aware of ..bla bla not eating bla bla fighting for heat bla bla security ect ect" Unless the animals health is at risk then telling them the proper way is a finely adjusted art from person to person. Be nice and try and do it like how you'd explain email to your BF or SO's grandmother. Be firm and knowledgeable without being rough or judgmental. Remember they cared enough to ask so use it as a chance to shine.