What constitutes a "grenade exploit"?

[Uncle Fester]

I'm aware of the nail gren and MIRV exploits, i.e. throwing them into the ceiling to hit people above you.  They are exploits, because these types of gren are NOT intended to pass through walls and floors.  No, I don't use them, and for the record I agree that they're inappropriate.

But what about grenades that ARE intended (by Valve, presumably) to go through walls/floors: concs, spy pills and EMP's?  Does intentionally using them in this way constitute use of a slap/kill/bannable exploit?

Note that I'm NOT talking about, say, repeatedly EMPing spawn on 2fort, which is obviously an attack on spawn and hence against the server rules.  However, throwing an EMP under the sniper balcony, or under the top-of-spiral room, seems perfectly reasonable and within the rules to me - but I've been told not to do so by an admin, because apparently that's an exploit.

By contrast, throwing spy pills under the sniper balcony on 2fort is a time-honoured tradition that no-one complains about (or gets slap/kill/banned for), but I cannot see how it is ANY different.

A formal ruling would be appreciated.

[Bishop]

Using pills and emps through walls is not an exploit and is allowed (unless you are attacking spawn exits). 

Nail and MIRV grenades through walls is an exploit.  The server has a fix preventing these exploits although some admins will still take action for attempting this exploit.

[Uncle Fester]

Thanks Bishop.  I will play accordingly.