Firewalls don't care about internet standards. I get an immediate response to a 1400 byte ping:

06:26:15.154205 IP 10.0.0.13 > perlmonks.pair.com: ICMP echo request, 
+id 46849, seq 0, length 1408
06:26:15.232493 IP perlmonks.pair.com > 10.0.0.13: ICMP echo reply, id
+ 46849, seq 0, length 1408
[download]

And no response to a fragmented 1500 byte ping:

06:26:32.986529 IP 10.0.0.13 > perlmonks.pair.com: ICMP echo request, 
+id 47105, seq 0, length 1480
06:26:32.986540 IP 10.0.0.13 > perlmonks.pair.com: icmp
[download]

BTW, I get a "time exceeded" message if I set the TTL to 16, but nothing if I set it to 17. It looks like Pair.com's border firewall is eating ICMPs.

06:34:53.777278 IP 10.0.0.13 > perlmonks.pair.com: ICMP echo request, 
+id 59649, seq 0, length 1480
06:34:53.777287 IP 10.0.0.13 > perlmonks.pair.com: icmp
06:34:53.862597 IP continental.car1.pittsburgh3.level3.net > 10.0.0.13
+: ICMP time exceeded in-transit, length 36
[download]

(And yes, I know ping doesn't use UDP.)