How would you handle this...?

My husband is a realtor and sometimes hosts "open houses" and I am amazed at the behavior of children that come into the homes. I will stop in to bring my husband lunch and witness children running through someone else's home, taking stuff out, messing up stuff, playing tag, etc. and the parents just ignore them and do NOTHING! It is almost like they just tune them out while they browse the home. They also come in and take 20 brochures just to be dumb, etc. and I don't think parents understand that realtors pay for those advertising brochures and they can get expense, sometimes around 5.00 a brochure to have them printed up! It makes me so angry and it is all I can do to bite my tongue, but my husband will not say anything to the parents because he said that if it offends someone that could be bad for his reputation...which as a realtor, his reputation is a big part of his job. He just "grins and bears" it and accepts it as a part of his job.