Set Field spells

my brother had some confusion with this on DN he took the other guys way but i would like to know if it is right

So opponent sets gear town in field zone my brother activates gates of Dark world
the opp says it does not take his card out does it?

also next turn he flips his field and kills Gates of dark world

The opponent here was correct. You can set Field Spells all you want, they don't negate an opponent's spell till it's actually activated. This is described in the 2nd paragraph here:

http://yugioh.wikia.com/wiki/Field_Spells

Edit: On a side note, once irl my friend totally pissed another friend he was playing off with this tactic XD Since we have like 5 people we know who play, we often play multi-way duels just for fun. so we were doing either a 5 or 6 way, and he set the Naturia forest for like the entire duel. The person who plays DW finally got Gates out, and the Naturia player flipped that and made him rage XD it was great

yes but the question was does the set field get destroyed when the none
set field gets active

ok, so say I have a field spell set. You can then activate another field spell of your own, and mine remains. If I choose to activate mine, yours would be destroyed.

Or, you could have a field already out, and I could set mine instead of activating it and yours would stay in tact until I choose to activate mine.

or most commonly, you'd have a field spell out, and I'd just play my own negating yours (but this is obvious).

I'm assuming either scenario 1 or 2 is what you're referring to.

@ Mimgrim- if you read the article I posted, it claims that there can only be 1 "face up" field spell, so theoretically one person could set one and the other have a face up one. The Game mechanics only destroy it when multiple are face up, with the older one being destroyed

If you have a set Field Spell and your opponent activates a Field Spell, your set Field Spell is NOT destroyed.

That is all that is needed to answer the question.

okay thank you guys!