pineapple YEA!

Question is, will "they" get here before we get there. Or, have "they" already been here.

Impossible.

Due to common sense, the planet may already have pre-exsisting life on it's surface.

Where there's life, theres diseases.
Where there's diseases, theres getting sick
Where there's people who have no immunity to the disease, theres eventual dying.

You cannot expect to put someone on a foreign planet and expect them not to contract a disease they are not immune to. Thats how the british killed hundreds of thousands of other people in the 1600's to 1800's with smallpox.

If there are diseases on this planet, let alone life that feeds off of other life. The chances are any bacteria there will feast upon us like fatpeople eatting big macs at a mcdonalds.