Normally I'd just leave them on, but I think Kobold Camp deserves a few years head start on sieges, for a number of reasons over Dwarf Fortress:
1. No exported wealth = fewer migrants, so you get a much slower, smaller population to fend off sieges.
2. Rarity of armor/weapons. Metal armor is all but unheard of (insanely expensive and only available from caravans), leaving you with low-quality bone and leather armor (they're equal in base protection, I think, but bone counts as plate). Weapons and metal arrows can ONLY be gotten from caravans, and even at max request, they only bring them in small quantities.
3. Kobolds are weak as hell compared to even dwarves.
4. An above-ground fortress, especially one big enough to house all the kobolds you'll want to bring in, is WAY easier to attack than an underground fortress, which usually has only one or two entrances and can be carefully guarded. Above ground, you're out in the open, and tall fortification towers are your best bet.
5. Low detection skills on kobolds mean sieges will often show up in the middle of town instead of on the map's edge. Shit sucks.