Can we use scarves or neckties instead of buying restraints?

You can for loose, symbolic wraps, but be careful. Fabric knots can tighten when someone pulls against them and can be hard to undo quickly. Keep ties loose, use the two-finger rule, and keep safety shears within reach. Purpose-made cuffs with Velcro or buckles are more comfortable and much easier to release, which is why they're recommended for beginners.