As a mother, am I out of line to do "head checks" on children before a sleepover???

Just as the school year ended, I found headlice on both of my children and myself!!!!!! It cost me about $450, time from friends and family to "nit pick" with me, taking everything to launder, then washing bedding every day for 2 weeks, cutting my hair and both of my daughters, frantically vacuuming the whole house, furniture and bedding every day, and without the valium I wouldve shaved our heads!!!!!!! There was a terrible outbreak of this and I DO NOT EVER want to go through it again. What I want to know is....is it rude of me to inform other parents of what we have been through, and, as a rule, anyone coming into the house I request permission to check for lice? Is this unreasonable??? One mother told me no way. I said that I just wasnt willing to take the chance of ever getting it again and that it wasnt an insult, I just have to be sure for our family~aand she had the option of not bringing her child. Does this sound crazy to anyone??? I dont think I am overreacting......