Wrap it in a template
tag as the template tag will not appear in the final rendered HTML:
<template v-for="hobby in hobbies">
<input type="checkbox" v-model="userHobbies" v-bind:value="hobby">{{hobby}}
</template>
Or even better, improve your markup semantics and use a label tag:
<label v-for="hobby in hobbies">
<input type="checkbox" v-model="userHobbies" v-bind:value="hobby"> {{hobby}}
</label>