Should my cat's collar say "should not be outside"?

My cat is microchipped and has a collar with a tag. 

The tag says: his name, address, and two phone numbers.

My question is, how will someone know to return him? I have seen many outdoor/indoor cats have collars, and never thought anything of calling their owner. Should my cats collar say something about him being an indoor cat only?

Have you heard about the Kitty Convict campaign ?

"Among the cats  that go missing each year, less than 5% of them manage to make their way home. This is partially because most cats lack ID collars, and cats seen outdoors are naturally perceived as strays. 

The folks  at Exploding Kittens  have come up with a delightful solution to this problem, with their ‘Kitty Convict’ Project. They propose that indoor cats be dressed in orange with an ID tag for two reasons—it is a bright color, and it brands your indoor cat as a “convict”. 

Read more: http://designtaxi.com/news/382411/T...-Solution-To-Finding-Lost-Cats/#ixzz3wbHyv6jv

What a great idea! Orange is so not my cat's color.... but worth his life in the end Thats a good idea to spread

My kitty's tag says (on the front):

Tiger

(xxx)227-0586 (my phone number)

I am microchipped

#:XXXXXXXXXX (microchip number)

(on the back):

Indoor Cat

Dr. Alex Lane (my veterinarian)

(xxx)741-xxxx (my vet's phone number)

My cat's tag is bright purple, so it stands out. 

In my county, not having a collar and tag on your cat is basically like signing a guarantee that you'll never see your cat again if they're lost. My cats are microchipped as an additional precaution, but microchips are only useful if they're actually scanned. In counties that essentially practice "euthanasia by proxy," cats are not likely to ever see the inside of a shelter. 

Here's a photo of my kitty with his "necklace." 

My kitty's current collar is actually an orange tiger striped collar. The brand is Beastie Bands.

I've seen tags that usually say something like "I'm lost, please return me to.."
Think that would convey the message

Wow the way you labeled your tag is actually a great idea because it covers all of the necessities. Maybe I should re-do mine! Thanks for the pic too, your kitty looks good in purple

My cats collar is very simple. It has the name, "indoor cat only, my cell number. Just 3 lines needed.