Generally, most people, whether they are Christians or not, understand the symbolism of a Crucifix, a representation of the suffering of Jesus, the Son of God. Similarly, many people understand the difference between a Crucifix and a Cross, the former bearing the figure, the latter is without. However, few would understand the difference between a crucifix which could be seen a heretical and one which is not. 
The Crucifix, from the earliest times of the Christian faith was seen as an expression of God's love for the world, in allowing His Son to die for the salvation and redemption of all people, which is the visual interpretation of Christ, with His arms outstretched, embracing us from the Cross. The fact that crucifixion was little more that a common form of execution under the occupying Roman authorities, is re-interpreted as a kind of divine message. Throughout the centuries, afterwards, Christians maintained this understanding, although there were some Christian groups who held a slightly different belief and rejected the presence of the 'corpus' or figure, believing that the occasion of Jesus' death was a 'once and for all event', not something which was to be seen perpetually, thus choosing the symbolism of an empty cross, which became popular with Protestantism, whilst the Crucifix remained the preferred symbol for Catholics, which is generally the same today.
However, in the 17th century, a Catholic Bishop of Ypres, named Cornelius Jansen, forged a theological movement, with other friends, within the Catholic Church, which challenged the accepted doctrine of universal redemption, claiming that Jesus did not die to save all people, but merely a selected number, 'the elect'. In order to emphasise this teaching the 'Jansenists', as they became known. had another kind of Crucifix made, which shows Christ hanging, arms almost straight up, not in the 'all embracing' style which had been universally acceptable for centuries before. Ultimately, the 'heresy' was condemned by the Catholic Church in the 18th century, which declared the Jansen Crucifix and their theology and doctrine to be heretical. Jansen Crucifixes are not common and often, because they are unrecognised, they are sold as just a normal Crucifix. Those which originate from the eighteenth century are sought after by collectors, most particularly those which have a carved bone corpus, which often are sold for many hundreds of pounds. The centuries since have erased the understanding of what they represented and it is not uncommon to discover them in churches on the Continent - they are no longer seen as a bad thing, just a crucifix like any other.