The cops can certainly get a search warrant with just one person saying so. Remeber you got to think of it as the government having a "war on drugs". Growing marijuana know matter how much you have is a felony is many places and felonies are no laughing matter. My cousin is a cop, he pulled a kid over that was on probation got him to snitch on where he bought it, long story short they picked up the guys garbage cans that night and found baggies in it. Bam multiple feloniy arrest, cops names in the paper and another battle won against the war on drugs. Its took 6 hours from the point the cop pulled the kid over to the drug dealers getting arrested. Since I did work at ups I know that the driver for them aren't usually too young. Atleast over the age of running through someones house for pot. Atleast where I live they make close to 30 bucks an hour? I'm sure he could buy it if he wanted to. try and keep a close eye on around your house for snooping and wandring eyes and hopefully your good to go.