tf_dropped_weapon_lifetime -1

sm_cvar does require sourcemod yeah, so you'd have to install a plugin on every server for it to work, which I don't see happening (not in etf2l at least), so it looks like there isn't an easy fix (right now at least).

tf_dropped_weapon_lifetime -1

This is clientside though, so you'd have to enable cheats, everyone will then have to do it manually, and then disable cheats again.

what's your main account then?

https://www.youtube.com/watch?v=GfPN0Y3WE8M

o:

https://www.youtube.com/watch?v=SxAjEP0BwlQ

Just tested, prec works fine for me, it's somewhere on your end.
I also doubt that if prec did break it would give you a message saying it's unsigned, because that applies to well, unsigned plugins, whereas prec is signed. If prec broke you would probably just crash whenever you'd use on of its commands (prec_record etc).

edit: I forgot to 7th page oops

Accuracy stats is (shots hit)/(shots fired), it doesn't have anything to do with damage. You can get an accuracy of more than 100% with the flaregun (and flamethrowers, but you don't see that happening often because you tend to spam the flamethrower a lot) because you only shoot once and set the other player on fire, and every tick of afterburn is another "hit".

I'm pretty sure 75%+ accuracy is considered fishy when it's on sniper, since most (high level) snipers don't get over 50% often. 75%+ accuracy on scout happens quite often and isn't fishy really.

https://www.youtube.com/watch?v=U90wtwmlysY

https://www.youtube.com/watch?v=N11h59YDP_c

https://www.youtube.com/watch?v=vFgMG6j5KIw

http://ge.tt/2zuuIu72/v/0?c

As JarateKing said it's because the texture is downscaled, it's really visible if you get closer to the wall:

http://puu.sh/dMJJ6/1d2886e761.jpg

I don't know anything about this really but if downscaling makes it look like this, could upscaling it to a really high resolution maybe make it vague / "flat" while not having this effect? I don't know if it's even doable or anyone tried it, but it's worth a try maybe?

It also kinda reminds me of mipmapping, if that's the proper term:

http://upload.wikimedia.org/wikipedia/commons/8/8a/Mipmapping_example.png

I don't know if it has anything to do with this though.

https://www.youtube.com/watch?v=LVCfMwGGV2k