Can you look at Tinder profiles without having an account?

Yes, You Can Look up Tinder Profiles Through looking at the Tinder photos which also may be used on ones Facebook. The other way is through using paid services search as, Cheater Buster.

Can you see people on dating sites without joining?

Virtually all dating websites will no longer allow you to search by simply browsing without registering. For example, you dont have to complete a lengthy profile for many dating apps if you choose not to, and there are very few requirements on most platforms when it comes to uploading pictures.