No, that doesn't sound right at all. Snakes are not social animals. People have a tendency to buy animals in multiples thinking that their new pet would be unhappy alone but that's certainly not the case when it comes to snakes. When people see snakes laying on top of one another, they may think it's some sort of act of affection - it's quite the opposite. There are so many reasons to keep snakes singly. The only reason (besides breeding) for keeping more than one snake in an enclosure is convenience for the keeper.
I'd also look for under tank heaters rather than lamps of any variety. If you're trying to maintain proper humidity, using a lamp is just going to hinder your efforts.