Orca you're so right, whatever happened to "pot luck", laying an extra place at the table etc. I don't care who comes to my house whenever.
I'm in Spain (till tomorrow, sob) and my husband was with me here for the first ten days, then went back to London for work. He was practically on his way out of here to leave for London when our son sent an email to say he'd be coming to ours for dinner that night "if that's okay" and would it be all right if he brought 2 friends? Husband said "Urgh" then "Sure" then "Seeing as I'm going to be cooking for 4 of us, why don't you invite XXX (another friend of ours) because his wife is away?" By all accounts they had a lovely evening although husband said he collapsed into bed exhausted once the young 'uns had all left. Makes life interesting.