You have no commitment to any of them, even after you accept. From the other side of the table, they expect many candidates to spend time preparing and intervie

You have no commitment to any of them, even after you accept. From the other side of the table, they expect many candidates to spend time preparing and interviewing and will only offer one the position - that's no different from you assessing multiple positions and choosing the one that fits you best. Having been there myself relatively recently, I can see why you'd initially feel guilty. If you get more than one offer, pick the one that's best for you and politely decline the others. They may come back with a higher offer if they really want you but I wouldn't suggest getting into a bidding war or you just risk annoying all parties and ending up with nothing. Finally, don't burn any bridges. If you worked with a recruiter, stay amicable - you never know when you'll be using their services again. Even if you applied directly, you may want to revisit their opportunities next time round.