[mikesabat]

You can feel ok about replying STOP to text messages from shortcodes. It's not impossible, but it would be an extremely bad process for an organization to have their OTP and their marketing messages (let alone spammy stuff) on the same short code.

There are short codes that are dedicated to OTP. Replying STOP to this number should not affect the ability for you to receive OTP for a different company login.

[beefnugs]

In canada : if it is a shortcode (very short phone number) STOP is probably supported at the carrier level.

Any regular phone number, you are probably just telling the spammer you are a real person with a working number and you will receive 10x more spam