we’ve hosted college kids before while their choirs/bands were on tour. and i can remember staying at some random houses over the years in college for various things. We’ve never received a gift, nor given one; but have received (and written) numerous thank you cards left in the morning. I think the point was trying to save $ by not getting hotels; so a delivered floral arrangement would have almost seemed contrary to the arrangements.
however, flowers are always sweet; and it’s never wrong to be kind.