Temporary Stair Barrier?

We're staying at a rental house next week with a recently-mobile
one-year-old and an eight-month-old. The main part of the house is on
the top of a very long staircase with a 7-foot opening. (Bannister
post on one side of the opening, wall on the other.)

Any suggestions for babyproofing? A pressure-mounted gate would be
more dangerous than nothing at all. Should I try to create a
temporary barrier of some sort with the help of my friendly
neighborhood home store, or should I resign myself to the fact that
we'll probably spend much of the week spotting children as they
stair-climb?