Agree completely with MarkS. These discussions are good but need to be kept in perspective to avoid getting carried away.
The CNCC region has of course placed several hundred resin bonded stainless steel anchors since the early 1990's and does not consider it necessary to test an anchor in a cave after placement (although of course there is a lot of testing gets done outside of the cave before that type of anchor is approved for use, and installers are trained to ensure good practice such as cleaning the hole out).
The CNCC has a very clear message to anyone caving using resin bonded anchors: https://cncc.org.uk/fixed-aids/safety.php
In summary, all users should check each anchor before use, and never rely on a single anchor.
Having been on a trip where a P-anchor with a little bit of movement was pulled out, the force required still took me by surprise (and those forces were of course straight outward, not downward). It really did not come willingly... it nearly broke the puller (in fact, after removing it, I jokingly commented that the anchor was fine after all and we should have left it in). It is also worth noting that of the anchors in the Dales with slight movement, this has been partly attributed to resin shrinkage over time and not an incorrect initial placement. These issues have been rectified with the IC anchors which use smaller holes, and newer generation resins.
But... these kind of discussions are always useful to share thoughts, and the experience/knowledge of people like Bob, Pete and others is great to share.
Regarding anchor placements... I hear a lot of general criticism about the placement of some anchors (too high, too low, too far apart, too close together etc). Most of this is just general banter with no real criticism intended, although when I was CNCC Secretary I did find myself at the wrong end of a few cavers' rants now and again. Often this is done without considering a number of factors such as the practicality of the installation, the availability of appropriate quality rock (there is a lot of poor quality rock at some pitch heads), the fact that the placement might consider higher water conditions, the accessibility of the site for a person holding a heavy drill, the limitations of the anchor/resin used at the time, or simply the personal opinion of the installer.
Not to say there aren't some questionable placements (there probably are)... but there are lots of factors to consider