RF learning code modules?

Hi,
Are the rolling /learning remote+receiver relay modules sold on ebay and the likes, secure once paired up?
That is, if i bought 5 sets and paired them separately, will they all work in the same house without interfering with each other? is it likely another remote on the same frequency could trigger the receiver relay?

here's a link to an example set:
http://www.ebay.com/itm/181502255050

Thanks!