Is it considered a scam if some has unmet trade obligations?

What im asking is that what if some wants an item, and says they pay half now half later but never follow up on payment. Is this an offence?

Absolutely. If you have a screenshot, or maybe even a chat log of this person promising to pay you half now, half later, and then a screen of your trade history (and paypal history, if cash was involved), showing they did not pay later, they can be marked as a scammer.

Thank you for your assistance

One more question, a guy i was trading with said there is a way to "send" keys without trade is this true?

No, there isn't. The only way to get keys is through trading or purchasing from the Store. Since all trades are performed through the item server, this should be impossible.

Thank you, thats what I thought.

well, there is a gift wrap, but those do cost as well, makes no sense to use those to "gift" a key to someone, especially if its a "payment".

You can't gift wrap keys, and you would still have to use the trade interface, even if it was wrapped.

ehm, not if you really "gift" it... you talk about trading wrapped items, not the final "gift" to some1. I never tried to wrap keys, so I didn't know that exception.

Wait, I'm sorry, I've lost what you're talking about. The only way to get items from one person's inv to another is through the trade window AFAIK, even if you use gift wrap you still have to trade the wrapped item to them. Have I missed something?

You can send a wrapped gift directly to someone without trading them.

I don't think it's possible to wrap keys.

I'll be honest, I never knew that. Whenever I've receive wrapped items, (skulls, jujus) it's always through the trade window.

well, one can wrap items, but to "unwrap" it, it must be "gifted", which doesn't require the trade window....