Sorry for Necroing a 5month old thread, but its the only one that seems to be discussing this topic. Has there really been no other discussion on grenades over a High barrier, or is this the best conclusion we got, that an attacker in same hex on the other side of a wall throwing the frag over is okay, but wall between two different hexes is a no-no?
Hand Grenades (except for antitank) doesn't have direct damage (this table was part of the latest update regarding this) so you can't aim for an individual target with them, you always aim for a hex and a barrier may block LoS to individual targets in a hex, the hex may still be visible and if the barrier is just a high wall, you can lob a grenade over the wall (this could be fun if the lob fails and land short). A grenade launcher can do direct damage but can of course also be used to target a hex, here you do the same, you target the hex which you can see.
If you can't see the hex because the target hex is two hexes away (for example) and the high barrier is in the hex between you and the target hex, then you need someone that aims for you.
Obviously UO has Blind Fire rules, but is "Over a Wall" the same as "through a doorway, breach or other aperture"? Getting close enough to the enemy that you can underhand a frag over a wall at them would imply to me that you're close enough to change the scale of combat to use Sectors instead of Hexes, thus "unlocking" (for lack of a better term) the Blind Fire rules from CQC in UO.
EDIT: After some more parsing through the rules, it would appear that RAW, "Cover" is a Terrain feature for hexes (page 57 Player Manual). If we count Cover as a Terrain Modifier (and Full cover does grant a -3 modifier to attacks at the Referee's discretion), then it would be ignored when targeting a hex with heavy weapons per the rules on page 71.
Full Disclosure, this is absolutely some bullshit rules lawyering lol, but without input from the designers, we don't really have much to go on for an answer to this question.
I do this in real life for fun on the weekends. #SurviveOmega #DoMoreWithLess