I will be in South Korea for about 3 days on the second week of July. I will most likely stay in Seoul and see some of the sights. I was planning on not booking a hotel (I've found a list of appropriate hotels) and just showing up. Do I need to book beforehand? I guess with the MERS thing, a lot of tourists are scared so the hotels won't be full.
Are you planning to sleep on the streets if the hotels are full :)?
All jokes aside, second week of July is the peak season for tourists in Seoul. I'm not sure which part of Seoul you're planning to stay at, but for popular sites (Gangnam, Yeoeuido, Gangbuk), I assure you that the hotels will be booked by then. Yes, even with the MERS thing, unless if MERS outbreak gets suddenly a lot worse within a month and nearly all of the countries issue a travel warning advisory to South Korea, but the chances of that happening is slim to nothing.
Plus you could typically get your refund when you cancel in advance, so what could you possibly have to lose?