Couple of things to note.. Contact cement is the same type of glue used in the "glue sniffing" cases of yesteryears.. Ventilation is key.. Most hardware stores used to be required to take down personal particulars when purchasing contact cement in the cans...
If you are trying to put the glue into a very narrow space, it's consistency is like honey and may not be able to spread very well. Also by thinning it down, you will get a thinner layer and won't get glue bumps under the thin laminate or wallpaper. If it is thick laminate then you can do it undiluted
