I mean, reading zeroed out memory is not really incorrect behaviour anyway. If you know that it was zeroed out, then you're really just reading memory that was initialised with a specific default value.

That being said, zeroing out everything you allocate will make it difficult for the kernel's paging system to defer allocating you a physical page until you actually need it, so you will need to be a lot more careful with your allocations if your application uses relatively large amounts of memory and you need to work with memory constraints.