I can think about three problems in the case
1) Glass is fragile, so if any significant load falls onto flask's or condenser's necks, it is a risk. Thus, the condenser should be light and have separate support, and the flask should have a second support for bottom or have a very small load (say, if it would be more than 100 g, I would hesitate.)
2) even round-bottom flasks does not necessarily have a perfectly spherical bottom, so fast stirring is absolutely out of question, and even gentle stirring for medium loads is not good.
3) If highly tilted, Allihn condenser may trap significant amount of liquid in its spheres. Dimroth and Inland Revenue condenser may trap some (little) amount of solvent on their coils too. Dimroth condenser MAY be used for refluxing even if should not ideally, and for solvents with high BP (say, toluene) should be OK. In fact, in case if violent reaction may occur it is PREFERABLE to use condenser with low internals resistance to straight float so the stream of boiling reaction mixture runned through the condenser in did not lift and smash it or teared the flask apart.
Actually, if no gas exhaust is expected, solvent, reactants and products do not have low bp and high toxicity I would prefer to reflux outside of the fume hood rather then tilted. It is OK. Even if some gas exhaust is expected, I would shrug of nonviolent non-toxic gas exhaust.